@Cypre55 Web searceh for "how to update pull request" should give decent explanation
DO address PR feedback in an additional commit(s) rather than amending the existing commits. This makes it easier for reviewers to track changes.
DO sync your PR branch with the upstream develop branch frequently resolving any conflicts if necessary. You can either git merge upstream/develop or git rebase upstream/develop with git push --force for the latter. The merge may make it easier for reviewers to track changes though.