Push back to remote from Pipelines

I'd like to be able to push back to the repository, maybe that's already possible but I tried some tricks and none of them worked. git push origin just gives an authentication failed error.

The use case we have is that we do deployment if a build is successful on the master branch (Tests pass, lints pass etc). Once the deployment is done we want it to tag the version with a tag to mark it as deployed, that way everyone knows exactly what commit is in what environment.