Include Audio from a Shared Video in Webex. Go to Share content Share content and select Optimize for text and images or Optimize motion and video.
If you selected Optimize for motion and video and your content includes sound, check the Share your computer audio check box.
We recommend this option if you’re sharing a video or animation that has sound. Everyone can hear what you’re sharing through the Webex Audio conference, whether they join from a phone, VoIP, or a video system.
Stereo audio is output as mono.
Mac users: The first time that you choose to share your computer audio, Webex prompts you to install audio drivers.
Select Install and follow the on-screen instructions, or select Cancel.
Select the content that you want to share.
You can change your optimization setting while you’re sharing content. Select Share at the top of the screen, 
and then select Share Content. 