Presence validation or Can't be blank validation is the first option you want to enable for most form fields. It allows you to be sure that user will input data to your form, instead of submitting blank form
Today I'd like to introduce new validation types: presence, validate only on submit. The best way to see how it works – real example.
Presence - this option does not allow a user to leave fields blank.
Validate only on submit - if you select this system feature it will check all the fields only after you press “Create” button.