The AutoFill tab in Toolbar Options enables you to automatically complete forms on the web. Enter your information and it's stored securely on your own computer. When you see yellow-colored form fields on web pages, you can choose to have Google complete the form for you with the information you've entered.
AutoFill stores personal data where only you can access it - your own computer. And your credit card number is encrypted and protected by a password you set. None of this information is ever sent to Google. In the Toolbar, the AutoFill button is enabled when you visit a page with fields that AutoFill can fill. Otherwise, the button in the Toolbar appears gray.
To complete forms on sites that you trust, just click the enabled AutoFill button. If you haven't entered any AutoFill information that applies to the current page, AutoFill displays the AutoFill tab page in the Toolbar Options window. Once you've entered your information on that page, clicking the AutoFill button will automatically complete a form.
If you want to see your data before it's filled into the form,
Shift as you click the AutoFill button. That
way you'll see the information you're providing and protect yourself from
pages that might try to capture information in hidden or hard-to-see fields.
If you don't want AutoFill to automatically highlight fillable fields, go to the More options tab and clear the checkbox "Automatically highlight fields that AutoFill can fill."
For now, AutoFill works only with English pages.
Here are the fields AutoFill can complete and what they mean:
If you forget your AutoFill password, go to the AutoFill options tab, click Add/Edit Credit Card, and then click the Forgot Password button. AutoFill clears your credit card number, so you can type it in again.
Note to web page authors: You can ensure that AutoFill will work on your pages by using field names defined in the ECML (Electronic Commerce Modeling Language) standard, found at http://www.ietf.org/rfc/rfc3106.txt.