certainly not the best tool but you use what you have! a business card is usually something like 1000px x 600px i think, around that. but there’s no DPI setting in AE, so I would maybe suggest making your comp 3-4 times the size (4000px) or higher. The other issue is colour, as you can only get an RGB image out, the printer will want CMYK. but most printers will convert for you (with some colour differences)
your source images are hopefully at least 3000px for this to work
good luck