If AutoFill doesn’t work in Safari on Mac
If you can’t fill in information you previously entered on websites, try these suggestions.
In the Safari app
on your Mac, choose Safari > Preferences, click AutoFill, then make sure “User names and passwords” is selected.Make sure any information you want to be filled in is saved in Contacts. Safari can fill in only contact information that is in Contacts. For example, if a form requires your phone number but it isn’t on your contact card, you must fill it in manually.
Make sure the webpage has fields AutoFill can complete.
Safari may be unable to tell which fields are for user name and password, credit card number and expiration date, and so forth.
If your Mac has Touch ID, and you want to use Touch ID to fill in user names and passwords or credit card information, make sure you select Password AutoFill in the Touch ID pane of System Preferences. See Change Touch ID preferences.
If AutoFill still doesn’t work, the website may not allow it.
To turn AutoFill off, choose Safari > Preferences, click AutoFill, then deselect the information you want to enter manually.