Github is not the only source code hosting facility - see a comparison of many others such as Gitlabs, SourceForge, etc
A source code repository is a file archive and web hosting facility where a large amount of source code, for software or for web pages, is kept, either publicly or privately. They are often used by open-source software projects and other multi-developer projects to handle various versions. They help developers submit patches of code in an organized fashion. Often these web sites support version control, bug tracking, release management, mailing lists, and wiki-based documentation.
Some of these do things better than Github, depending on what your own needs are, and many also offer to import from Github. So before making any hasty moves, it is always well worth looking at the alternatives. There even used to be a Google one!
Wikipedia has a nice comparison of costs and features at https://en.wikipedia.org/wiki/Comparison_of_source_code_hosting_facilities.