Autofill

Autofill is a feature in software and websites that automatically fills in form fields with data previously saved by the user, or suggested by a service, to speed data entry. In web browsers and mobile operating systems, autofill commonly supplies names, addresses, email addresses, phone numbers, login usernames, and sometimes payment or card details. The data can be stored locally on the device or synchronized to an account or password manager, enabling form filling across sites and apps. When encountering a form field, autofill matches the field type and offers a stored value or inserts it directly, with users able to review, edit, or remove entries. Developers can influence autofill with the HTML autocomplete attribute, which can indicate common field types such as name, email, address lines, or postal code, and sometimes more sensitive tokens like cc-number or cc-exp. Browsers and OS-level services (for example, password managers and autofill frameworks) provide the actual filling logic and user interfaces.

Security and privacy considerations: Autofill stores sensitive information, including passwords and payment details, so it should be used on trusted devices and in secure contexts. On shared or public devices, autofill can expose data, and attackers may use phishing forms to capture credentials. Best practices include using trusted password managers, enabling two-factor authentication, using autocomplete="off" for sensitive fields where appropriate, and ensuring sites use HTTPS.

Beyond forms, autofill features also exist in spreadsheet software to extend data patterns across cells, based on user-selected templates.