Git and Subversion
Help+Manual's version control interface comes with pre-configured scripts for synchronizing with both Git and Subversion. In addition to this, there is also an option for syncing with any other version control system that supports scripted access.
Integrated Team Foundation Server and Visual Source Safe support has been removed
As of Help+Manual 9, we have removed the integrated support for the sunsetted Team Foundation Server. Even Microsoft is now switching to Git for their own version control needs, and this is reflected in their purchase of the GitHub platform. If you absolutely must continue using TFS, you will need to use the Custom Version Control option and set up scripted synchronization with your TFS repository.
Support for Visual Source Safe has also been removed. This legacy system is now completely obsolete and should no longer be used.
Custom version control interface
Help+Manual's interface to version control is fully scripted and open, which means you can configure it yourself to synchronize with any VCS that supports scripted access. You can also reconfigure the scripts for Git and Subversion yourself, for example to include user names and passwords in the parameters passed to the system.
Originally called "git" (all lower case), Git was developed by Linus Torvalds, the creator of Linux, and is now the premier version control system worldwide. It is extremely reliable and amazingly fast. It is a peer-to-peer system that does not require server software. Every user has the entire repository, and thus every user could be the central repository that everyone else synchronizes with.
In practice, you will put a central copy of the repository on a server. Then all your users will synchronize with that. You can host it yourself, or use excellent free services like GitHub and Bitbucket.
The older Subversion is still an excellent system, but it has some disadvantages compared to Git. The main one is that it is a centralized system requiring installation of both client software on the user's computer and a full server installation with the repository on the central server. Users don't have a copy of the repository, just references to it. This means that the central repository is a potential single point of failure, unlike Git where every user has a full copy of the entire repository.
Because of this, there are fewer public hosting options for Subversion than for Git, and they tend to be more expensive. Quite a few web hosting providers support Subversion, but in many cases you will have to manage and configure the server installation yourself.