When you want to protect your web form from submitting by all web users it is very handy to add password protection. Just set login and password and give it to the users who has to be able to submit form
In this blog post you can see how to protect your form using login and password.
For example, you need to use "New form". Users can add records to the "New form" database only after they confirm their access to the form by filling login and password fields.
Please, go to the Forms module and create a form with "login" and "password" fields. It's a single line field type.
For field "Password" you should do the same steps.
The last step. Go to the Customize & Integrate menu. For our first form select "Redirects" submenu. After your users have successfully submitted the login and password, you can redirect them to another website or webpage. In our case we will redirect users to the "New form" direct page. For this enter in this field "New form" direct url. You can find it in the Customize & Integrate module - Form widget. Click on the direct link and copy it.