Some time ago I added info(files) that must be private. Removing from the project is not problem, but I also need to remove it from git history.

I use Git and Github (private account).

Note: On this thread something similar is shown, but here is an old file that was added to a feature branch, that branch merged to a development branch and finally merged to master, since this, a lot of changes was done. So it's not the same and what is needed is to change the history, and hide that files for privacy.

I have found this answer and it helped:

git filter-branch --index-filter 'git rm -rf --cached --ignore-unmatch path_to_file' HEAD

Found it here https://myopswork.com/how-remove-files-completely-from-git-repository-history-47ed3e0c4c35