You might be looking to turn your Ubuntu 18.04 Laptop into to WiFi Hotspot to share your Broadband Connection/Internet Connection across you for your other devices ( Mobile, Ipads, etc ).
So you are just a few clicks away to achieve it, believe me it's as easy as you do within your smartphone.
Steps.
Click on the top right buttons and click on the WiFi option. in the dropdown select Wifi-settings.
Click on 'Turn On Wi-Fi ' option from the button.
Click on the extra options ( 3 dots ), now Click on 'Turn On Wi-Fi Hotspot'
The Hotspot is now active!!
you can find the password and details.
Now any of your devices can discover this Hotspot and connect to it with the given password.
Video Tutorial: