1) Please click on the money manager icon shown below. Navigate to accounting settings then payment types.

1 > Click on Money manager

2 > Accounting settings

3 > Payment type

2) Click on Add new to add a new payment type. You can use the opt option to opt a payment type while receiving payments. You can also use the payment gateways for your transactions. Here you can also add a processing fee, if any. 

 3) To add a new payment type >> Click on add new >> please select the Payment group >> Payment type and click on save.