diff --git a/sample/doc/assets/behavior.js b/sample/doc/assets/behavior.js
index 1e7cc05..7073b32 100644
--- a/sample/doc/assets/behavior.js
+++ b/sample/doc/assets/behavior.js
@@ -156,18 +156,7 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "billing/ListPlans",
             "title": "ListPlans"
           },
-          "depth": 2,
-          "outline": [
-            {
-              "type": "heading",
-              "data": {
-                "level": 1,
-                "title": "Get List of Plan Sample",
-                "slug": "get-list-of-plan-sample"
-              },
-              "depth": 1
-            }
-          ]
+          "depth": 2
         }, {
           "type": "file",
           "data": {
@@ -321,7 +310,96 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "invoice/CreateInvoice",
             "title": "CreateInvoice"
           },
-          "depth": 2
+          "depth": 2,
+          "outline": [
+            {
+              "type": "heading",
+              "data": {
+                "level": 1,
+                "title": "Create Invoice Sample",
+                "slug": "create-invoice-sample"
+              },
+              "depth": 1,
+              "children": [
+                {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Invoice Info",
+                    "slug": "invoice-info"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Merchant Info",
+                    "slug": "merchant-info"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Address Information",
+                    "slug": "address-information"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Billing Information",
+                    "slug": "billing-information"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Items List",
+                    "slug": "items-list"
+                  },
+                  "depth": 3,
+                  "children": [
+                    {
+                      "type": "heading",
+                      "data": {
+                        "level": 4,
+                        "title": "Tax Item",
+                        "slug": "tax-item"
+                      },
+                      "depth": 4
+                    }, {
+                      "type": "heading",
+                      "data": {
+                        "level": 4,
+                        "title": "Tax Item",
+                        "slug": "tax-item"
+                      },
+                      "depth": 4
+                    }
+                  ]
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Shipping Information",
+                    "slug": "shipping-information"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Create Invoice",
+                    "slug": "create-invoice"
+                  },
+                  "depth": 3
+                }
+              ]
+            }
+          ]
         }, {
           "type": "file",
           "data": {
@@ -547,18 +625,7 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "lipp/GetUserInfo",
             "title": "GetUserInfo"
           },
-          "depth": 2,
-          "outline": [
-            {
-              "type": "heading",
-              "data": {
-                "level": 3,
-                "title": "Obtain Access Token From Refresh Token",
-                "slug": "obtain-access-token-from-refresh-token"
-              },
-              "depth": 3
-            }
-          ]
+          "depth": 2
         }, {
           "type": "file",
           "data": {
@@ -576,18 +643,7 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "lipp/ObtainUserConsent",
             "title": "ObtainUserConsent"
           },
-          "depth": 2,
-          "outline": [
-            {
-              "type": "heading",
-              "data": {
-                "level": 3,
-                "title": "Get User Consent URL",
-                "slug": "get-user-consent-url"
-              },
-              "depth": 3
-            }
-          ]
+          "depth": 2
         }, {
           "type": "file",
           "data": {
@@ -1487,7 +1543,56 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "payouts/CreateSinglePayout",
             "title": "CreateSinglePayout"
           },
-          "depth": 2
+          "depth": 2,
+          "outline": [
+            {
+              "type": "heading",
+              "data": {
+                "level": 1,
+                "title": "Create Single Synchronous Payout Sample",
+                "slug": "create-single-synchronous-payout-sample"
+              },
+              "depth": 1,
+              "children": [
+                {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "NOTE:",
+                    "slug": "note"
+                  },
+                  "depth": 3,
+                  "children": [
+                    {
+                      "type": "heading",
+                      "data": {
+                        "level": 4,
+                        "title": "Batch Header Instance",
+                        "slug": "batch-header-instance"
+                      },
+                      "depth": 4
+                    }, {
+                      "type": "heading",
+                      "data": {
+                        "level": 4,
+                        "title": "Sender Item",
+                        "slug": "sender-item"
+                      },
+                      "depth": 4
+                    }
+                  ]
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Create Payout",
+                    "slug": "create-payout"
+                  },
+                  "depth": 3
+                }
+              ]
+            }
+          ]
         }, {
           "type": "file",
           "data": {
@@ -1569,7 +1674,45 @@ f.event={add:function(a,c,d,e,g){var h,i,j,k,l,m,n,o,p,q,r,s;if(!(a.nodeType===3
             "pageTitle": "sale/RefundSale",
             "title": "RefundSale"
           },
-          "depth": 2
+          "depth": 2,
+          "outline": [
+            {
+              "type": "heading",
+              "data": {
+                "level": 1,
+                "title": "Sale Refund Sample",
+                "slug": "sale-refund-sample"
+              },
+              "depth": 1,
+              "children": [
+                {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Refund amount",
+                    "slug": "refund-amount"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Refund object",
+                    "slug": "refund-object"
+                  },
+                  "depth": 3
+                }, {
+                  "type": "heading",
+                  "data": {
+                    "level": 3,
+                    "title": "Sale",
+                    "slug": "sale"
+                  },
+                  "depth": 3
+                }
+              ]
+            }
+          ]
         }
       ]
     }, {
diff --git a/sample/doc/invoice/CreateInvoice.html b/sample/doc/invoice/CreateInvoice.html
index a75c1ea..2791f9d 100644
--- a/sample/doc/invoice/CreateInvoice.html
+++ b/sample/doc/invoice/CreateInvoice.html
@@ -50,7 +50,10 @@ detailed breakdown of invoice</p></div></div><div class="code"><div class="wrapp
 
 <span class="hljs-variable">$items</span>[<span class="hljs-number">0</span>]-&gt;getUnitPrice()
     -&gt;setCurrency(<span class="hljs-string">"USD"</span>)
-    -&gt;setValue(<span class="hljs-number">5</span>);</div></div></div><div class="segment"><div class="comments "><div class="wrapper"><p>Second Item</p></div></div><div class="code"><div class="wrapper"><span class="hljs-variable">$items</span>[<span class="hljs-number">1</span>] = <span class="hljs-keyword">new</span> InvoiceItem();
+    -&gt;setValue(<span class="hljs-number">5</span>);</div></div></div><div class="segment"><div class="comments "><div class="wrapper"><h4 id="tax-item">Tax Item</h4>
+<p>You could provide Tax information to each item.</p></div></div><div class="code"><div class="wrapper"><span class="hljs-variable">$tax</span> = <span class="hljs-keyword">new</span> \PayPal\Api\Tax();
+<span class="hljs-variable">$tax</span>-&gt;setPercent(<span class="hljs-number">1</span>)-&gt;setName(<span class="hljs-string">"Local Tax on Sutures"</span>);
+<span class="hljs-variable">$items</span>[<span class="hljs-number">0</span>]-&gt;setTax(<span class="hljs-variable">$tax</span>);</div></div></div><div class="segment"><div class="comments "><div class="wrapper"><p>Second Item</p></div></div><div class="code"><div class="wrapper"><span class="hljs-variable">$items</span>[<span class="hljs-number">1</span>] = <span class="hljs-keyword">new</span> InvoiceItem();
 <span class="hljs-variable">$items</span>[<span class="hljs-number">1</span>]
     -&gt;setName(<span class="hljs-string">"Injection"</span>)
     -&gt;setQuantity(<span class="hljs-number">5</span>)
@@ -58,7 +61,11 @@ detailed breakdown of invoice</p></div></div><div class="code"><div class="wrapp
 
 <span class="hljs-variable">$items</span>[<span class="hljs-number">1</span>]-&gt;getUnitPrice()
     -&gt;setCurrency(<span class="hljs-string">"USD"</span>)
-    -&gt;setValue(<span class="hljs-number">5</span>);
+    -&gt;setValue(<span class="hljs-number">5</span>);</div></div></div><div class="segment"><div class="comments "><div class="wrapper"><h4 id="tax-item">Tax Item</h4>
+<p>You could provide Tax information to each item.</p></div></div><div class="code"><div class="wrapper"><span class="hljs-variable">$tax2</span> = <span class="hljs-keyword">new</span> \PayPal\Api\Tax();
+<span class="hljs-variable">$tax2</span>-&gt;setPercent(<span class="hljs-number">3</span>)-&gt;setName(<span class="hljs-string">"Local Tax on Injection"</span>);
+<span class="hljs-variable">$items</span>[<span class="hljs-number">1</span>]-&gt;setTax(<span class="hljs-variable">$tax2</span>);
+
 <span class="hljs-variable">$invoice</span>-&gt;setItems(<span class="hljs-variable">$items</span>);
 
 <span class="hljs-variable">$invoice</span>-&gt;getPaymentTerm()
diff --git a/sample/invoice/CreateInvoice.php b/sample/invoice/CreateInvoice.php
index 1f38547..6562d7f 100644
--- a/sample/invoice/CreateInvoice.php
+++ b/sample/invoice/CreateInvoice.php
@@ -70,6 +70,13 @@ $items[0]
 $items[0]->getUnitPrice()
     ->setCurrency("USD")
     ->setValue(5);
+
+// #### Tax Item
+// You could provide Tax information to each item.
+$tax = new \PayPal\Api\Tax();
+$tax->setPercent(1)->setName("Local Tax on Sutures");
+$items[0]->setTax($tax);
+
 // Second Item
 $items[1] = new InvoiceItem();
 $items[1]
@@ -80,6 +87,13 @@ $items[1]
 $items[1]->getUnitPrice()
     ->setCurrency("USD")
     ->setValue(5);
+
+// #### Tax Item
+// You could provide Tax information to each item.
+$tax2 = new \PayPal\Api\Tax();
+$tax2->setPercent(3)->setName("Local Tax on Injection");
+$items[1]->setTax($tax2);
+
 $invoice->setItems($items);
 
 $invoice->getPaymentTerm()