Pass hidden user info from IS to a Gravity form?

You have to use the GF feature “Allow field to be populated dynamically”.
You write a GF filter that pulls the email from the url using get_query_var().

add_filter('gform_field_value_email', 'pf_populate_email'));

You will need to tell WordPress to honor the custom query parameter (via a query_vars filter) so that get_query_var() will see it. See
https://codex.www.ads-software.com/Function_Reference/get_query_var
for an example.

The code will probably be in your theme’s functions.php

So do you put this in Advanced, default value: add_filter(‘gform_field_value_email’, ‘pf_populate_email’));

or does it go in functions.php?

Sorry, my bad.

The value on the form, in this example, is “email” (no quotes)

GF then takes that value, prefixes it with “gform_field_value_” and calls the resulting function that’s defined for that filter. E.g. “gform_field_value_email” has an associated function “pf_populate_email”

Ok.

1. Add “email” to the hidden field default value

2. add “add_filter(‘gform_field_value_email’, ‘pf_populate_email’));” to my functions.php

3. add “<?php get_query_var( $var ) ?>” to my functions.php page.

Do I need to customize any of that code?

Am I missing anything?

A few items:

• You have to add a filter that tells WordPress to evaluate the custom query parameter. See
  https://codex.www.ads-software.com/Function_Reference/get_query_var#Custom_Query_Vars
  for more info.
• Change item three to define the function “pf_populate_email”. Its contents will be the statement in item three (minus the PHP declaration)