I learn Git and Using VSCode and just learn the commit "amend" command and now trying it on origin (GitHub).
I can't find any way to do this. Do I need some external tool to do that I don't see any "push amend" from the Git menu in VSCode
You do not push amend to the remote repo.
git commit --amend allows you to include all current staged changes to your last commit in the local repo, instead of creating a new commit.
Let say you committed all changes but forgot to include a file include_me.js.
You may run git add include_me.js, then git commit --amend to amend your last commit.
As mentioned by knittl, if you amend an already-pushed commit, you have to force-push the branch. Beware, if anyone has pulled the branch before you force push, they will have to reset their local branch.