Understand origin and upstream

Remote names describe roles. origin normally means the repository you cloned or your writable fork. upstream commonly means the original project in a fork workflow.

Inspect remotes

git remote -v
git remote get-url origin

Add or change a remote

git remote add upstream https://github.com/<owner>/<repository>.git
git remote set-url origin https://github.com/<your-username>/<repository>.git

Sync a fork

git fetch upstream
git switch main
git merge --ff-only upstream/main
git push origin main

The fast-forward-only merge keeps your fork's main aligned without creating a merge commit.