Use this forum for technical support and general questions related to GEO my WP plugin and its core add-ons only. For technical support and general questions related to any of the premium extensions please open a new premium support ticket.
Using the Premium Settings extension, you can add additional text input fields to the search form to filter results by custom fields. Note that at the moment the Custom fields filters can be added as a text input field to the search form. there is no option to filter custom field using dropdown menus, checkboxes and others.
let me know if that helps or if you have any other questions.