First, you will need to go to PayPal Developer and click on “Log into Dashboard” in order to log in. You will need to use your PayPal Account Credentials to access the PayPal Developer Dashboard.
After you log in hover your mouse over Testing Tools and click on Sandbox Accounts.
Here you will need to click on “Create Account” to create your first PayPal Merchant and Buyer Sandbox Account.
To create a PayPal Merchant Sandbox account go to Testing Tools-> Sandbox Accounts -> and click on “Create Account”. Select Account Type -> Business (Merchant Account), set it up, and click on “Create Account”.
To create a PayPal Personal Sandbox account go to Sandbox -> Accounts and click on “Create Account”. Select Account Type -> Personal (Buyer Account), set it up, and click on “Create Account”. This account should be used when testing payments.
To view the PayPal Merchant Sandbox Account API Credentials click on Manage accounts and then on “View/edit account”.
Inside the Profile, you need to copy the Email ID.
Then you need to click on “API Credentials” and you have to copy the Username, Password, and Signature.
After you copy the PayPal Standard Test API Credentials go to your website -> Dashboard -> Paid Member Subscriptions -> Settings -> Payments -> Payment Gateways -> PayPal Standard and paste your PayPal Standard Test API Credentials and click on “Save Settings”.