Test SSH Connection

ssh -vT git@github.com

Show URL

git remote show origin

Set URL

git remote set-url origin git+ssh://git@github.com/username/repo-name.git

Add a Remote

git remote -v
git remote add upstream https://github.com/ORIGINAL_OWNER/ORIGINAL_REPOSITORY.git
git remote -v

Sync with Remote

git fetch upstream
git checkout main
git merge upstream/main
git push