Form fields don’t show up

I’m trying to create my first form with a custom field and am not able to get the field to display. The goal is to provide a set of fields that users can edit to provide / manage additional information about themselves.

I start with a “Profile Form” Form type and add the fields “First Name”, “Last Name” and add a “Number” field with meta key “walk_num” to the form.
Form

Field

I create a page with the shortcode, and view the page and only get First Name and Last Name rendered:

rendered page

I tried setting the field to be “required” and it still doesn’t render.

Any clue would be appreciated.