What autofill does here
Autofill Forms enters the details you saved in a profile. It is not Chrome’s password saver, and it does not type card numbers.
Standard details
A profile can hold a title, first and last name, email, phone, company, job title, address lines, city, state, postal code, country, website, and date of birth. Empty fields are skipped.
What it will not enter
Passwords and payment card numbers stay out of the profile. Use Chrome’s own tools for those. If a page asks for them, fill them yourself.
How a match is chosen
The extension looks at the field name, the label, and the placeholder. A keyword rule you wrote for that profile wins over the built-in guess. The value is entered with the same kind of input events a typed character would produce, so many modern pages keep it.