When you choose Delete field as an action for a validation rule, a field is deleted from the form. It is as if that field were not filled in on the form.
When you choose Confirm field, then you must confirm the contents of the field when you use Verify to process the form. It is as if Confirm handwritten were selected in the field definition. Confirm field can be used on these field types:
Warning: If you choose Confirm field, avoid infinite loops.
Specify a name for the action. This is just a label to help you remember what the action does.
Specify which field is to be deleted or confirmed.
Click OK.