From the "Customer" tab, search for the Customer you wish to resend the request to using the search bar to the top right and enter the Customer name, mobile, email or reference.
Once you have found the Customer, click 'Manage' (the arrow to the far right). This will bring up the Customer overview screen, with the invitation details in a small window to the top right.
There are two buttons at the bottom of this window, reading "RESEND SMS" and "RESEND EMAIL". Select the one you would like to resend, then confirm your choice. The Customer will now receive the initial invitation link again, which will also include the automatic reminders if they do not complete the on boarding process that day.