Password protecting your form means users cannot access you form without first entering a password.
To password protect your form, you must log in to emailmeform.com > mouse over the form you want to protect > click on the "Protect" icon:
Enter your selected and secure password (you can opt to show password while you write if it is easier) > then click "Save":
View the form on the front-end (as your users will see it), and you will notice that the form is password restricted: