Pre-populate Wordpress User Email in embedded form


I'd like to be able to pre-populate an embedded Pabbly checkout with a user's wordpress email address and name. I've already seen the suggestions at the link below.

query parameters

I've tried adding PHP code that recreates the embed URL like this using the Code Snippets plugin:

// Get current user's email address
$user_email = wp_get_current_user()->user_email;

// Build the URL with user's email address
$pabbly_url = "" . $user_email;

// Output the URL as a variable
echo $pabbly_url;

And then using the variable: $pabbly_url in the Pabbly embed code, but I can't get it working.

Is there a way to make this work?

It would solve a big problem for me.