Before you print
How big should it be?
Rule of thumb: printed width ≥ scanning distance ÷ 10. Pick the surface above and the studio sizes the code for you, then checks the printed module size against what a press can actually hold.
Questions people actually ask
The code points to a tiny UseQR redirect that checks the device type and forwards it: iPhones to your App Store page, Android phones to Google Play, everything else to your fallback link.
Open your app's page in each store and copy the URL. The App Store link contains apps.apple.com, and the Play Store link contains play.google.com — we check both so a typo can't slip onto a printed poster.
They go to your fallback link if you set one — your website or landing page works well. Without a fallback, they are sent to whichever store link you provided.
One is enough. If your app is only on one platform, every scanner is simply sent there, and you can regenerate the code with both links once you launch on the other store.
Yes — the generator and the redirect are both free, no signup. Note this is the one code type that relies on a UseQR URL to do the device detection.
Want the detail? How app download QR codes work — the payload format, what scanners do with it, and where it breaks.