In order to broadcast, you would first need a separate iRacing account (www.iracing.com).

Once you have the iRacing software installed, you would access the camera view.

You would then need to use a third party application to broadcast. 

Here are two examples and videos that may be helpful:
https://www.youtube.com/watch?v=r3IR3fkqmSI
and
https://www.youtube.com/watch?v=stMBmiEwvYE 

Or if you looking to hire someone for your event, you can try RaceSpot and Podium.

This is iRacing's official broadcasting policy as of April 2, 2021:
https://ir-core-sites.iracing.com/members/pdfs/20210405-iRacing_Broadcast_Policy_dated_Apr_02_2021.pdf