Not sure which state the OP is in but with the Covid Check in's I'd much rather scan a QR code as I walk into a shop than stop and fill in all my personal details on a piece of paper.
But you can just have a card with the QR code on it....
In Chicago, proof of vaccination is now required for bars, restaurants, and entertainment venues (not grocery stores, etc., but the State mask mandate applies indoors).
There are smart-phone based apps available that are accepted (must include photo ID to verify that you are, in fact, the Fred Flintstone on the vaccination record).
However, my experience starting in October when concerts, operas, and theaters united to require this is that the digital thingies are much slower at ID check than my simple procedure:
We keep our original CDC Covid records safely at home in the file cabinet, and use 1x photocopies (which are acceptable) that we carry. Folding this over once is the right size to go over a driver's license, and that fits nicely into a shirt or jacket pocket. It is much faster to pull out the paper copy, unfold it, and hold the license to show everything important to the checker than what I see in front of me with people pulling out there phone and finding the appropriate bit.