When you invite people to your organization from Control Hub, they get a link to get started. If they haven't signed up after two days, they'll automatically get a reminder email. You can manually resend the invitation at any time.
Reminder emails are not currently available for Cisco Webex Meetings users.
From the customer view in https://admin.webex.com, go to Users, filter the Status column to display people with an Invite Pending status.
Under Actions, for a person with an Invite Pending status, select .