3 POSITIONS TO PUT A BARCODE ON POSTCARD Do I need a barcode on postcard? How to do it? Where should a stamp be placed on a barcoded postcard? That is also the reason why you need to leave space for the barcode. The Post Office prints a barcode on each component 5/8ths of an inch from the bottom during sending. It is better to leave this space blank; if they are unable to print directly on it, they will instead apply a sticker with a readable barcode to the bottom. See more: https://barcodelive.org/barcode-on-postcard