You might be taking advantage of Google Forms which helps you create HTML forms instantly and use it by simply embedding a one line HTML code snippet. Yes, Google forms are really powerful as it helps you create HTML forms with different controls on it and with validation. You can create polls and surveys etc using Google forms.
When someone fills the form on your website, the data/information provided by the visitor is stored in a spreadsheet. You can use this spreadsheet to do various data manipulation or to simply store the data.
In a general scenario when a user fills the form on your website, the data is only pushed in the spreadsheet and you have to check for the new entries by opening Google Docs. But what if you want to get the notification instantly. So that an email is sent when the forms is successfully submitted. To set the notification follow this simple workaround.
Now when next time someone fills up the form, an instant notification will be fired to your email address.
Hope that helps.