You can create up to 12 different Payment Methods in CheckIn, each with a corresponding button that will appear wherever payments are recorded. Click on the "More" button to the right in the Taskbar, select "Admin" from the drop-down menu, then "Company," then "Payments Setup".
You can add, delete or edit payment methods in this list, sort them by assigning numbers, and change each Transaction Type by selecting from a drop-down menu. (It's not necessary to have different Payment Methods for MasterCard, VISA, Amex, et cetera -- you can set a single Payment Methods for all Credit Cards.)
You can use this tool to configure different Payment Methods such as Synchrony payments, Gift Cards, or Coupons.