Anyone at your company (with a company email address) can sign in to Gem Scheduling through their Google or Microsoft 365 account. For Microsoft 365 users, this means they must have a license.
However, some information is limited by the user's permissions within your calendar system. For example, if a user does not have access to other people's calendar events in Google or Outlook, they will not be able to see interviewers' conflicts if they try to create a schedule.