Google recently completed the cross-platform rollout of a feature allowing Google Apps customers to share links to Hangouts video calls so that external meeting guests may request to join if not explicitly invited.
Previously, video calls shared with the link required someone in the Apps domain of the Hangout video call to accept those requesting access on the web. With today’s launch, we’ve enabled this accept or reject functionality in the latest version of the Hangouts iOS app.
To accept or reject a request to join a video call on your mobile device, tap the ‘Accept’ or ‘Decline’ button in the pop-up screen that appears when a guest is requesting to join.
This functionality is coming soon to the Hangouts Android app.
Rapid release and Scheduled release
reference by google.com