You can resend invitations from the Provider Invitations page. You can get here by selecting Provider Invitations from the Connections menu on the purple header. You may need to scroll down to see the Invitations for [Provider] section.
For each invitation, you can see a row detailing their Invite Code, Phone number, Name, the Process the invitation is in, the Invitation Date, and the ability to edit any invitations that are in Draft, or are Sent (but not Connected). If you click the edit link, you will be able to edit the details of an invite or resend the invite by clicking the purple Resend button.