Hi, I like to uninstall games when I'm done with them, but I don't know how to with itch.io? I'm a new user and have practically no idea how to do so. Help

The easiest way is to use the Itch application.

If not, it will depend on each game, most games on Itch are usually portable, meaning deleting what you downloaded is enough.

If the game came as an installable (normally not recommended for security reasons), you can type "remove programs" in the Windows search bar and open the "add and remove programs" application that will show you a list of all the programs you have installed on your Windows.