hide the top bar in ubutnt code example
Example: ubuntu top bar hide
sudo apt install gnome-shell-extension-autohidetopbar
For Ubuntu 20.04
Alt + F
Type "r" and press Enter to reload gnome shell
sudo apt install gnome-shell-extension-autohidetopbar
For Ubuntu 20.04
Alt + F
Type "r" and press Enter to reload gnome shell