A Watch Party is a great feature to use to watch games with your friends and family. When you initiate a Watch Party, the rest of the participants will display at the top of the screen, with the game you're watching in the center of the screen. You'll be able to speak and see the other participants throughout the game.
To start a Watch Party, select the game you want, then tap the Watch icon in the right sidebar and click Start Watch Party. You'll then be prompted to enter the email addresses of the participants you wish to invite.
Note that in order to participate in a Watch Party, participants must have an active subscription.
A Watch Party does not permit multiple users to be logged in to the same account from different devices.