1. The payments tab can be found in the settings page as shown.
2. All the available payment options are listed here.
3. Click on any of the options.
4. Enter the payment details and click on save.
5. You can now choose the default payment option while creating a customer.
6. While creating a new invoice, you can set the default payment option too.
7. When the customer logs in through the customer area, they can make payments using the set payment option.