If Safari isn’t automatically filling in information on websites, try these suggestions.
Choose Safari > Preferences, click Passwords, then make sure “AutoFill user names and passwords” is selected.
Note: The “AutoFill user names and passwords” option in the Passwords pane is equivalent to “User names and passwords” in the AutoFill pane of Safari preferences. When you select one, the other is also selected.
Make sure any information you want to be filled in automatically is saved on your card in Contacts. Safari can only fill in contact information that’s on your card in Contacts. For example, if a form requires your phone number, but it isn’t on your 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 AutoFill still doesn’t work, the website may not allow it.