When you package an app in App Inventor and choose “Show Barcode” it generates a QR code that you can use to allow others to install your app. Unfortunately, people can only install it if they are App Inventor users. This is especially problematic while App Inventor is in its invite-required mode.
There is a work-around. This screencast demonstrates a process for downloading an android executable (.apk) from app inventor, getting it on the cloud, and generating a QR code that others can download.