Steam Login

Hello Cadu de Castro Alves,

You can use the provided action hook for login form: user_registration_login_form_end. E.g.

function ur_add_stream_login() {
     // Steam login button
} 
add_action( 'user_registration_login_form_end', 'ur_add_stream_login' );

And for registrtion form: user_registration_form_registration:

function ur_add_stream_login_after_reg() {
     // Steam login button
}
add_action( 'user_registration_form_registration', 'ur_add_stream_login_after_reg' );

Hope this helps!