Sure! Let me clarify that the previously generated link is a change password ticket URL that when clicked on, sends the user to your change password email template, which you have repurposed as an application sign-up invitation email.
My apologies for not being clear about the implementation.
Let me clarify that there are 2 options to send the email to the user:
If you use the Management API to create a Change password ticket, you must send it to your user using an external email provider. You will have to implement and enforce this action on your end. Typically, this is an extra step since it would require you to connect all the pieces together.
Otherwise, you can use the Authentication API Change password endpoint to send the email to the user without using an external email provider. I recommend this method as it’s simpler and has less overhead.