You can start in rgb mode and the background can be white. Just set the eye icon in front of the background color map layer to off in the output file, and the background will be transparent. The transparency of business cards to be printed does not depend on whether the background is white or transparent, but on the choice of printing materials. Select transparent PVC material, and convert the design draft into Cmyk mode after the design is completed. If the printing factory produces the version, it may need to be converted into AI or coreldraw format for plate making and printing.