Update your local repository to keep it up-to-date.

$ git pull origin main

(...)

remote: Enumerating objects: 6, done.
remote: Counting objects: 100% (6/6), done.
remote: Total 10 (delta 6), reused 6 (delta 6), pack-reused 4
Unpacking objects: 100% (10/10), 1.07 KiB | 78.00 KiB/s, done.
From https://<your_forked_repo>
 * branch            main       -> FETCH_HEAD
   f187d39..e437f49  main       -> origin/main
Updating f187d39..e437f49
Fast-forward
 ./test.cpp | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Show the working tree status.

$ git status
On branch main
Your branch is up to date with 'origin/main'.

nothing to commit, working tree clean

Add original repository and call it upstream.

$ git remote add upstream https://<original_repo>.git

List the remote connections. Upstream should be seen here.

$ git remote -v
origin  https://<your_forked_repo>.git (fetch)
origin  https://<your_forked_repo>.git (push)
upstream    https://<original_repo>.git (fetch)
upstream    https://<original_repo>.git (push)

Fetch upstream.

$ git fetch upstream main
remote: Enumerating objects: 14, done.
remote: Counting objects: 100% (14/14), done.
remote: Total 47 (delta 14), reused 14 (delta 14), pack-reused 33
Unpacking objects: 100% (47/47), 8.08 KiB | 243.00 KiB/s, done.
From https://<original_repo>
 * branch            main       -> FETCH_HEAD
 * [new branch]      main       -> upstream/main

Switch to your master branch.

$ git checkout main
Already on 'main'
Your branch is up to date with 'origin/main'.

Apply upstream changes into your local repository.

$ git rebase upstream/main
Successfully rebased and updated refs/heads/main.

See changes.

$ git status
On branch main
Your branch is ahead of 'origin/main' by 11 commits.
  (use "git push" to publish your local commits)

nothing to commit, working tree clean

Force push the changes into your remote repository.

$ git push -f origin main