All members in your workspace can see and join every Room without an invitation or link.
That said, if you do need to share a link or put one in a calendar invite, you can:
Click the Room where the meeting is taking place
Click Room Link below the Room name at the top of the Lobby
The link is in your clipboard ready to share or put in your calendar invite
The Room link works for both workspace members and people outside your workspace.
Keep in mind:
To invite a workspace member while a meeting is happening, use Add People to select them from the list to invite.
Or, toggle to Room Link to quickly copy the meeting URL to share with people outside your workspace.