By default, speakers receive an email as soon as they are assigned to a session.
The email will have 2 links, one to access the My Speaking Schedule tab in the Virtual Event Hub, and the other is the unique Accelevents Studio URL for the session.
If you don't want them to receive the email invites yet while you're adding them to the session, you can turn it off from the Agenda Settings:
Resending Speaker Invites Per Session
When using this option, you can only send speaker invites one by one. All speakers assigned to a session will appear inside the session edit menu. Click the edit/pencil icon at the far right side of the session name to open the editor and navigate to the speaker list:
From here, you can send each speaker the email invite for the specific session by clicking the small calendar icon:
Resending Speaker Invites Per Speaker
If ever you want to send a speaker multiple sessions, open the Speakers tab, locate the speaker, click the edit/pencil icon on the far right side and open the sessions list.
All sessions assigned to the speaker will show up:
Click on the small calendar icon below every session to send the email invite:
Resending All Session's Email Invite to All Speakers
Lastly, you can send all speakers all their session invites by going to the Agenda settings: