Like any other Android devices, installation of apps downloaded from third-party or unknown sources are blocked on Huawei mobile phones. If you downloaded apps in APK formats from the web and want to install them on your Huawei phone, you have to enable this feature on your phone first. Here’s how to enable authorization for application installation from unknown sources on Huawei mobile.
Open Settings on your Huwei phone, scroll down to find Security & privacy, tap on to open it, then scroll down and choose More settings on the next screen.

Tap on ‘Install apps from external sources‘, you will see a list of apps on the next screen. Choose Files app from this list, then grant Files app the permission to install APK files, or external apps downloaded from third-party or unknown sources.

Simply touch the On/Off toggle next to Allow app installs to turn it on.
After that, go to download apps from website to your mobile phone or transfer APK files from computer to your mobile phone. Tap on the APK file and confirm the installation, review permissions the app requires and follow on-screen tips to install it.
Wow. Thanks. Just got a Huawei Mediapad M5 9 and have been searching *hours* for this information. Thank you so much.
Hi bro, I did all these steps , it is still showing that app is not installed
I’m having theame issue on my Mate20
Huawei Mate 20 Pro. I have just made a mistake and let 10.1 Emui update to be installed. Now I can not install any external apk. Above solution doesn’t work. When I try to install an apk screen just blinks and return to previous screen.
I cant tab the allow button. it wont let me grant permission
thanks !!!