One of the steps on the DevOps journey is the consolidation of tools. This means that, at some point, you might be asked to migrate sources from one source control system to another. This means that companies might decide to move all of their sources from GitLab or Subversion to Azure Git Repos. There are multiple options available to you to do migrations like these.

The most likely event is that you will receive requests to move sources to one or more Azure Git repositories. Possible sources are other Git repositories, TFVC, or Subversion. There are tools and approaches available to do such a migration while retaining the change history of the original repository.

If there is no procedure available or you must import sources from another system, you can also fall back on creating a new empty repository and initialize that with an existing code base. The disadvantage of this is that all history will be a lost this way.