Last updated: 2021-09-15
Works with CiviCRM 5.20 or higher.
The form processor is used to handle the submission of a form on an external website in CiviCRM. You can define your inputs (fields) and then define the actions. An action could be create a contact, add contact to group, etc.
See Using CiviCRM form processor extension to handle form submissions from an external website for an how to use the form processor with an external Wordpress Contact Form 7 or with an external Drupal 7 and Webform website.
In the screenshots below, two GIFs of the form processor in action, one with submitting the form from an external Wordpress site and one of the configuration.