Disable AutoComplete for forms
User Configuration\Administrative Templates\Windows Components\Internet Explorer
Prevents Internet Explorer from automatically completing forms, such as filling in a name or a password that the user has entered previously on a Web page.
If you enable this policy, the Forms check box appears dimmed. To display the Forms check box, users open the Internet Options dialog box, click the Content tab, and then click the AutoComplete button.
If you disable this policy or do not configure it, users can enable the automatic completion of forms.
The Disable the Content page policy (located in User Configuration\Administrative Templates\Windows Components\Internet Explorer\Internet Control Panel), which removes the Content tab from Internet Explorer in Control Panel, takes precedence over this policy. If it is enabled, this policy is ignored.
If you enable this policy after users have used their browser with form automatic completion enabled, it will not clear the automatic completion history for forms that users have already filled out.