You have probably run your App Inventor apps through AI Companion. The AI Companion is a great tool for quickly loading the app you are developing on to your phone for testing. However, the AI Companion does not install the app on to your phone, like a regular app.
To install the app on your phone, use the Build menu “App (provide QR code for .apk)”. You will see a progress bar appear on your screen as App Inventor prepares the app for installation on your phone. Behind the scenes, it is creating a “.apk” file which is the type of file used for all Android applications.
If you are not familiar with QR codes – a QR code is a method of encoding data into a matrix. A smart phone camera takes a snapshot of the QR code matrix and software on the phone extracts the encoded data. In this case, the data is the URL or web address where a temporary copy of your .apk file has been stored. You’ll need to install a QR code reading app (available for free in the Google Play store) and use it to scan the code. Then, follow the on screen prompts and icon to download the .apk file to your phone and then install the app on to your phone. Once installed, it will appear in your list of apps just like any other app.
If you do not wish to use the QR code method, you can also build and download the .apk file directly to your computer. Once the .apk file is on your computer, you could email the .apk file as an attachment – such as email it to yourself! Then, on your phone, fetch your email and download and install the apk file on to your phone.