If you are wondering how you can be marked as a contributor to your game project, the person who has uploaded and submitted it to the jam on itch.io has to go to the games dashboard (edit game) - and then go to the Admin menu. From there you can generate links for people to be marked as contributors to your game which will also allow you to vote on other submissions in the jam. You will need to provide your itch.io username to this person in order for them to generate the link.
If you joined the jam and did not submit anything but would still like to vote on the games, you can leave a comment here and I will mark you as a Judge so that you can vote on the games. You will need to accept a link that I generate for your username specifically.