Push backwards current HEAD, uncommitting last commit but keeping files
git reset HEAD^
Reset to a past HEAD, removing unpushed changes (hard) or keeping modified files (soft)
git reset HEAD --[hard|soft]
If it's the last commit pushed, push backwards your HEAD and then push the head to ORIGIN
git reset HEAD^
git push origin +HEAD
# Recommended to push only specified branch HEADs:
git push origin +HEAD:<branch_name>
If lots of commits have been pushed there's no way to erase only one commit...
But you can revert the changes using:
git revert <commit_hash>