Several anti-spam solutions exist on Drupal to prevent the submission of forms (contact, newsletter subscription, etc.) by more or less well-intentioned robots. Without wanting to be exhaustive, we can use the Honeypot and Antibot modules which provide (different) non-intrusive defence mechanisms, or the captcha / recaptcha modules which ask the visitor to respond to different challenges before allowing him to submit the form.
Like display modes that allow you to display an entity in multiple ways, Drupal 8 allows you to create multiple form modes that can be used on entities, whether they are users, taxonomy terms, contents or any custom entity. Let's discover here how to use these form modes, from their creation to their use to customize the input of a user's information, for example.