Field Configuration: To add Hidden field in a form, go to User Meta >> Forms. Add a new form or edit an existing one. In the Form Builder menu click Hidden Field from right sidebar of Extra Fields section. Then you will have a configuration panel. Configure your Hidden field by using this configuration panel.
Hidden field is used to pass information without showing the field in front-end.
This part consists of Meta Key and Value.
Meta Key: Use meta key to save field’s data. Without defining the meta key, field data won’t be saved. You must define a meta key for this field. This is unique identification key for the field. E.g. hidden (unique and no space).
Value: Define a value to pass this without showing.
This part consists of Admin only, Make the Field as Shared and Conditional Logic.
Admin only: To make this field available only for admin check admin only.
Make Field as Shared: To make this field as a shared field to use the field in any form just check Make this field as shared.
Conditional Logic: To apply conditional logic to this field Enable Conditional Logic. To know about conditional logic, read Fields Basics.
Nothing will appear in front-end for hidden field.