Braintree integration documentation (#12775)

* Braintree integration documentation

* Cleanup documentation

erpnext/docs/user/manual/en/setting-up/integrations/braintree-integration.md

@@ -0,0 +1,39 @@
+# Setting up Braintree
+
+To setup Braintree, go to `Explore > Integrations > Braintree Settings`
+
+## Setup Braintree
+
+To enable Braintree in your ERPNext account, you need to configure the following parameters:
+
+- Merchant ID
+- Public Key
+- Private Key
+
+You can setup several Braintree payment gateways if needed. The choice of payment gateway account will determine which braintree account is used for the payment.
+
+![Braintree Settings](/docs/assets/img/setup/integrations/braintree_account.png)
+
+On enabling service, the system will create Payment Gateway record and an Account head in chart of account with account type as Bank.
+
+![Braintree COA](/docs/assets/img/setup/integrations/braintree_coa.png)
+
+It will also create a payment gateway account. You can change the default bank account if needed and create a template for the payment request.
+
+![Payment Gateway Account](/docs/assets/img/setup/integrations/payment_gateway_account_braintree.png)
+
+After configuring the Payment Gateway Account, your system is able to accept online payments through Braintree.
+
+## Supporting transaction currencies
+
+```
+"AED","AMD","AOA","ARS","AUD","AWG","AZN","BAM","BBD","BDT","BGN","BIF","BMD","BND","BOB",
+"BRL","BSD","BWP","BYN","BZD","CAD","CHF","CLP","CNY","COP","CRC","CVE","CZK","DJF","DKK",
+"DOP","DZD","EGP","ETB","EUR","FJD","FKP","GBP","GEL","GHS","GIP","GMD","GNF","GTQ","GYD",
+"HKD","HNL","HRK","HTG","HUF","IDR","ILS","INR","ISK","JMD","JPY","KES","KGS","KHR","KMF",
+"KRW","KYD","KZT","LAK","LBP","LKR","LRD","LSL","LTL","MAD","MDL","MKD","MNT","MOP","MUR",
+"MVR","MWK","MXN","MYR","MZN","NAD","NGN","NIO","NOK","NPR","NZD","PAB","PEN","PGK","PHP",
+"PKR","PLN","PYG","QAR","RON","RSD","RUB","RWF","SAR","SBD","SCR","SEK","SGD","SHP","SLL",
+"SOS","SRD","STD","SVC","SYP","SZL","THB","TJS","TOP","TRY","TTD","TWD","TZS","UAH","UGX",
+"USD","UYU","UZS","VEF","VND","VUV","WST","XAF","XCD","XOF","XPF","YER","ZAR","ZMK","ZWD"
+```