When processing a card through Renterra, the payment information will automatically be saved under the Customer's page
Add Customer's Payment Method
Go into the Customer's page
Click the three dots in the top right hand corner.
Click Settings.
Click the plus icon for the Billing Section of this page.
Choose "Add New Credit Card" or "Add New Bank Account."
Type in the Payment information and Click "Save."
Delete Customer's Payment Method
Follow Steps 1-3 of the previous section.
Under the "Saved Payment Method" Section, press the trashcan next to the method you'd like to delete.