App Installation bug

Hello please I build an app for someone and can't install it due to phone goggle security. I have to tell him the process needed to install. Now is there a way I can build my own app without this stress to install on phone just like normal app I do download on Play store.

It's not a bug, it's a feature of Android security, to protect naive users against apps not vetted by Play Store guardians.

You can bypass those checks in the device settings, and by checking all those error messages for loopholes allowing you to bypass the roadblock.

Thanks for your feedback.
How do I bypass those things am I doing them on the app builder or the phone itself.
Any code involved to by pass it.

I forgot to mention the phone browser as another roadblock.

Sometimes they refuse to download things like .apk files unless you insist, following links hidden behind details of the error message.

I'm sorry I don't have more specifics for you.

Alright thanks so much.