Virtually all Shopify store themes use either a cart page or a cart drawer. If your theme is enabled to use a cart drawer, you can typically control the setting in your 'Customize' section.
Other than checking your settings, you can also identify which cart type you're using just by clicking on the cart icon in your store. If the store takes you to a new page with /cart in the url, you are using a Cart Page. If the store slides open the cart from the side of the screen, you are using a Cart Drawer.
The GovX ID Military Discount app can integrate with both the cart page and the drawer. In fact, promoting your military discount offer in the cart is proven to be the most successful way to get traction for your program.
Learn how GovX ID integrates with your cart: