I have a solution on Azure DevOps. It uses GIT as a version control. Now I have added a new user to the repository. I just want this user to be able to work on 2, 3 projects (I have about 35 projects in solution). So I would like to do something like - this user may read all projects, build them, but can only change these projects...
How can I accomplish that?
You can't. The design of Git does not allow this kind of access-control. but, you can create a specific branch for him and give him permissions only to this branch.
Another option is to lock the master with branch policies (that it recommended anyway - also if you gave him permissions only to his branch) so now merge to the master will require a PR and you can review the changes before.