Hi @jr219,
Welcome to the Auth0 Community !
Since the user is created manually using the Management API, then basically the only part remaining on the user’s part is to set up a password, so that is why
A user invitation is basically a change password link repurposed as an invitation
as mentioned in our documentation about Sending Email Invitations for Application Signup.
In addition to that, you can check out this Article which provides more information and all the instructions needed to use Auth0’s password change emails to send email invitations to the users.
Hope this helps the case, but others as well.
Thanks,
Remus