I use GitHub. This is not ideal; GitHub is a proprietary, trade-secret system that is not Free and Open Source Software (FOSS). I am deeply concerned about having to use a proprietary system like GitHub to contribute to FOSS projects.
Alternative, fully FOSS code forges exist. For all my own projects, I use sourcehut. If sourcehut is not for you, have a look at Codeberg instead.
I urge you to read about the Give up GitHub campaign from the Software Freedom Conservancy to understand some of the reasons why GitHub is not a good place to host FOSS projects.