During a meeting, you can raise a virtual hand to let people know you want to contribute without interrupting the conversation. 

Just select Raise your hand  in the meeting controls.

Everyone in the meeting will see that you've got your hand up. 

Meeting presenters will also receive a notification that your hand is raised, and they can lower your hand once you've had a chance to talk. 

Select Show participants   to see a list of everyone in attendance. Anyone who's raised their hand will have an icon next to their name. When multiple people raise their hands, they'll be listed in the order in which they raised them.