If you cant enable or Turning on Wi-Fi Hotspot in ubuntu 20.04 Focal Fossa default Gnome desktop.
You can solve this problem easily using this method
1. Press Alt+F2 on keyboard to bring up ‘Run a Command’ pop up, then input nm-connection-editor and press Enter.
2. When the ‘Network Connections‘ window pops up, click plus (+) button on the bottom-left to create a new connection.
3. When the ‘choose connection type‘ window pops, seleft Wi-Fi from the drop-down box.
4. After clicked the ‘Create…’ button, do following settings in next window.
Type connection name: whatever as you want (for example ubuntu-share)
Type SSID: whatever as you want (for example sharing network)
Select Mode: Hotspot
5. Open Wi-Fi security tab and Select WPA & WPA2 Personal then set your password (for example 8765431)
6. Finalstep Open Wi-Fi Settings window, and click on the top-right menu and select Connect to Hidden Network…
then choose connect to your previous created network.