Code repositories are applications to store software source code. It adds functionality like control version, team chat, etc.
Git is an open source version control system that provides code repositories. As the code is publicly available, it can be implemented by anyone.
There are different companies offering Git repositories as a service. This post lists some popular solutions for code repositories.
List of Code Repositories as a Service
Code repositories as a Service, it means, in the cloud:
GitHub is a subsidiary of Microsoft since 2018.
It is free for open source projects.