You'll need to first check your service's or agency's GPC instruction or regulation. Your agency/organization program coordinator also should be able to help you with this question. At the DoD level, you can refer to the DoD Government Charge Card Guidebook for Establishing and Managing Purchase, Travel, and Fuel Card Programs via section A.1.2 GPC Purchasing starting on page A-9.

https://www.acq.osd.mil/asda/dpc/ce/pc/docs/guides-docs/DoD_Govt_Charge_Card_Guide_06_03_20.pdf