At the present time Visa, MasterCard, American Express, Apple Pay, Google Pay, and PayPal are the accepted forms of payment. To change your wallet funding source in the app:

1.        Click on the Profile icon at the top right of the home screen to get to My Account
2.        Click Payment
3.        Click GreenP Account under My Wallets
4.        Click Payment Type
5.        Existing payment method which funds the current wallet will be displayed
6.        Click Add New on the top right of the screen
7.        Choose from Credit Card, PayPal and Apple Pay/Google Pay options

After completing steps 1 through 7, follow the next steps for each payment method.

Credit Card
1.        Enter your card details
2.        Click Save Card

PayPal
1.        Enter your PayPal login when prompted or create a PayPal account
2.        Confirm Address and Payment card for automatic purchases  
3.        Click Agree & Continue

Apple Pay/Google Pay
1.        Select card for use with Apply Pay/Google Pay