It might not be good advice, but that was not what OP asked for.
My comment was meant as a beginner-friendly way to install Mullvad VPN on Ubuntu, and not unsolicited advice telling them to learn something that should not be needed for daily computer usage. And while adding the repo might be the better solution, that would require the use of the terminal, and as multiple people have proven to me, that wouldn’t be a friendly way to introduce Linux to someone just starting out.
You don’t teach someone to swim, by dropping them in the middle of the pacific.
And click the “download .deb” button (It says underneath “Works on Ubuntu 20.04+, Debian 11+ (64bit only)”. As long as your Ubuntu is up-to-date, this will work fine)
you get a file (“MullvadVPN-2023.6_amd64.deb”) you can run just like on Windows (similar to MullvadVPN-2023.6.exe)
opening the file should open a GUI for installing the file
Keep in mind, to update Mullvad VPN, you would need to download a newer .deb file (after an update is released). It shows the latest version above the download buttons, below the “Mullvad VPN for Linux text” This is the same as how it is on Windows
Edit: This is not intended as good advice, just a simple way to install Mullvad VPN. The smartest solution would be to add the repo.
2nd Edit: While this is how Mullvad provides their software, it is never ideal to install random .deb packages or add third party repos without being sure that the ones who provided the package/repo is trustworthy.
<a href="">https://distrochooser.de/</a> is a great tool that help to understand what the different distros can do.
Also, you should probably know that selecting a distro is more about selecting the underlying OS and less about the UI (DE). Most distros support the top 5 Desktop Environments (DE for short). And selecting a DE can be just as important.