Android Question Help shared my app

You can copy the app apk from objects folder of your project to your phone, and share or if the app is installed on your phone, you can use xender app to share

thank you but I would like to share the application of my application thanks to the share button! I have a library that does it but it is incompatible with android 8

There are two steps required:
1. Copy the APK to the other phone.
2. Install the APK.

This means that the APK itself must be included in your app files. You can then send it with Bluetooth and use a file explorer to install it. It cannot be done automatically unless another app of yours is already running on the other phone, like B4A-Bridge.