Validation types: can't be blank (required field), validate only on submit. The best way to see how it works – real example.

Login to QuintaDB online database

Create new project using templates

Go to the Form builder menu

Ok, so now we have a form with fields. Good. Let's have a talk about validation. Open the field editing page by clicking left mouse button on the field or using context menu:

Open the Validation tab and mark "Can't be blank" and "Validate only on submit" options

Can't be blank - 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.

Also, you can make Required field from the Form builder menu: