Creating my own gift-cards and UPC's
We do not sell enough gift cards to invest in plastic ones and personally, I hate plastic ones. I create my own gift cards and would like to create UPC's that I can attach to the cards to easily scan when selling and I'd like to print from to my Zebra printer - 100-200 at a time.
I need help understanding the following:
1) UPC rules for this staring with a 4 and ending with another static #. (how many digits does this need?)
2) How to. print the stickers on the Zebra ZD410 from an excel / google sheet file (anyone have a link for this?)
3) Workarounds for selling via my shopify when customers want to buy something online.
Thank you community!