Where can I view different form modes?
You can try these modules.

https://www.drupal.org/project/form_mode_control https://www.drupal.org/project/form_mode_manager

I prefer form_mode_control. Form_mode_manager create a view form mode for all content types.

These modules can be restricted with permissions. But I prefer https://www.drupal.org/project/field_permissions; it is more acurated by field.