Github is the industry standard. It’s easy to use and is packed with features, it’s also quite flexible in how much it provides for free.

Codeberg is a github clone but open source and nonprofit. People are weary that github is owned by Microsoft so if you’re a privacy conscious person that likes open source, it’s a good option.

I’ve never used Gitlab but from what I’ve heard it’s more enterprise oriented, focused on providing solutions for companies rather than something simple for everyone. You can also self-host it if you want it on your own servers.