When a user creates a form, its expiration date will be set by default at this interval in the futur. Ex : if a user creates a form on 01/01/2020 and the expiration value is set to '5', the form will expire by default on 02/05/2020. Insert '0' if you don't want forms to expire.
Describe what your form is about. This will appear above your form.<br/> If you want to display pictures, you should consider using an external image hosting service, like <a href='https://framapic.org' target='_blank'>framapic.org</a>.