Hi @dev40 ,
Welcome to the Auth0 Community!
The “Send Email Invitation for Application Signup” is for the Auth0 database. The invitation basically is a change password link. For Social accounts, the social channel is the IdP, so we can not update password. Could you please share some context regarding why you only want to send email invitation for application signup for Google accounts?
One possible solution for your use case is to set up Account Linking, where users link their Auth0 database accounts with their Google Account. This article explains how to use the Auth0 Account linking extension, and this article explains how to implement client-side Account linking.
Hope this helps!