API Username:
Enter an API user name you've obtained from PayPal
API Password:
Enter an API password you've obtained from PayPal
Gateway URL:
Enter the PayPal gateway. Usually, https://api-3t.paypal.com/nvp
API Credentials
Client Side SSL
Select this option if you are using a certificate.
3-token Authentication
Select this option if you are using a signature.
Signature:
Signature for 3-token Authentication
Certificate Password:
Password of the Certificate file for Client Side SSL
Full file path of Certificate file for Client Side SSL.
Test Connection
Click this to check the connection to the gateway using the credentials provided.