As mentioned above you will need to set the Account you want updated. This is done in the Account Receivable Type menu.
For the Start Date, it is automatically set to today’s date; we recommend changing this to the first day of the membership year, so that if you enter a payment with this tender type with an earlier date than today the credit card surcharge will apply.
Next, make sure to set the Surcharge amount, the second will give you two options you can choose from, Percentage or Dollar Value.
Select the Billable Item is what will show up on the charge.
Charge to other account is where you want the charge to go if you do not want it to show on the intended account.
The screenshot below is an example of a surcharge setup.