Your account will automatically reload using the credit card, Apple Pay/Google Pay or PayPal on file. Reload amounts are configurable with a minimum reload of at least $20.
To change the auto charge amount:
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) Tap the desired Reload Amount (it will flash to show you have tapped but will not be highlighted)
5) Click Save
Note that in situations when the replenishment amount does not cover the cost of the parking transaction you are trying to initiate, the necessary amount will be charged in the increments chosen by you during the signup process or at the auto-recharge setting under Green P Account. For example, the parking fee is $30 and you have $5 in your account. It would be necessary to replenish the account with $20 (minimum required load) plus another $20 to cover the cost of parking. At this point you would have $15 in your account. The amount charged will not be two $20 charges, but one charge for $40.