how to view viedo in full screen

Hello Dear User! '

Please contact the consumer department for further assistance:

https://consumer.huawei.com/en/support/hotline/ 

Hi user! u can follow these:

Apply Full Screen Display
Most apps installed on your phone will automatically adapt to display correctly in full screen.

For apps that don't, go to Settings > Display & brightness > More display settings > Full-Screen Display, and toggle on their switches. Enabling Full-Screen Display may cause some apps to display incorrectly, for instance, by being improperly stretched.

Show the Notch
Go to Settings > Display & brightness > More display settings > Notch, and select Default.

If you want to show or hide the notch for a specific app, touch Custom, select the app, then select one of the following options:
Auto
Show notch
Hide notch

Hide the Notch
Go to Settings > Display & brightness > More display settings > Notch, and select Hide notch.

Extend the Screen Display to the Edges
You can extend the display of your phone to the screen edges.

Go to  Settings > Display & brightness > More display settings > Edges, then you can:
Enable the switch next to an app to extend the display for it.

Enable Show for all apps.

Go to  > Reset app preferences, and your phone will enable the switch only for compatible apps.

https://consumer.huawei.com/en/support/content/en-us00753709/

Thanks!