If you’ve committed a number of git commits using a wrong user.name or user.email value, you can re-write previous commits with:
git filter-branch --commit-filter ' if [ "$GIT_COMMITTER_NAME" = "Old Name" ]; then GIT_COMMITTER_NAME="new-name"; GIT_AUTHOR_NAME="new-name"; GIT_COMMITTER_EMAIL="new-email"; GIT_AUTHOR_EMAIL="new-email"; git commit-tree "$@"; else git commit-tree "$@"; fi' HEAD
Note that this will re-write all commits on the current branch matching the if condition which may or may not be what you’re looking for, so be careful. push the changes back to your remote origin as needed.
This is based on answers to this question here.