iSolutions explains how Credit Cards work in Dynamics GP: You must set up your Company Credit cards before you process credit card transactions for customers or vendors.
— Read on www.isolutionspartners.com/2019/06/07/dynamics-gp-credit-cards/
Dynamics GP Credit Cards – iSolutions Partners Dynamics GP Credit Card
Archived post from 2019. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.