The de facto standard for hosting and collaborating on code
Git repository hosting with issues, pull requests and CI (Actions). Most open source lives here.
Yes, personal private repos are free; advanced team features are paid.
You can do basics on the web and in GitHub Desktop, but learning Git pays off.
Information and links are accurate as of the time of writing and may change. Always verify on the official site. This is an independent guide, not affiliated with the listed services.