Guests are individuals external to your workspace. They can be invited to join a call and enjoy in-call features depending on your plan.

They can also send videos and media to your support team if they're given a stream to do so.
‍
Users are teammates you invite to your workspace. They can access to the dashboard. Depending on the role you grant them, they will have different permissions such as create or schedule call, create and manage teams, listen call recordings, etc.