Make sure that nobody is left out of your Hangouts by inviting them to your call. After you’re in a chat or video call, you can easily invite other people to join.
To add people to a video call that’s already in progress:
Step 1: After you are in the video call, click Invite people person+3 at the top of the screen.
Step 2: Enter email addresses or open up your video call to a circle or organization.
Step 3: Click Invite.