I highly recommend as mentioned before the use of git, the reason #1 is because any VCS is a safety net in case of disaster. Look for the “In case of fire: git commit, git push, leave the building” sticker. The code may be stored somewhere else, but no in a laptop that can break down, be stolen or whatever... even a local network server is not the most safe place for something as valuable as code.
Number 2. Traceability of changes, who did what, when, etc... Merges, Undo. Number 3. Diff the magical tool for #2 and many more cases. Number 4. Branches Number 5. Tagging versions, releases, etc..
You may find more information about one of the most common git workflows here: https://nvie.com/posts/a-successful-git-branching-model/
I know that using git can be intimidating at first, but it’s a good investment for a skill, and a must have for any development team.
About your issue with text case, avoid using Tortoise, I know most people use it as a GUI for git, as it was very common for SVN, so it may be first choice, instead use command line, or a another GUI like github desktop or the SourceTree from Atlasian.