To delete a Payment Method follow the steps and/or watch the video below:
1. Go to "Tools" >> "Payment Methods".
2. Click on the 
icon beside the Payment Method you want to delete.
3. You will get a pop-up message asking "Are you sure you want to delete this record?".
4. Click "Ok".
Note: If you are unable to delete a Payment Method it is because you cannot delete any of the system default types. You can however edit the type and untick the "Supported" option, which will stop it from appearing in bookings.