I have set up AutoFill in iOS 12 as described:
"On the Home screen, tap Settings.
Tap Passwords & Accounts > AutoFill Passwords.
Turn on AutoFill Passwords.
(Deselect iCloud Keychain)
From now on, you’ll be able to fill and save passwords, without ever opening the 1Password app."
To fill a password , I do this:
"To fill or save a password, visit a website in Safari or open an app, and tap a username or password field. If you have a Login saved for the website or app, you’ll see your username above the keyboard. If not, you’ll see, [Key Symbol] Passwords."
The Login is saved in my 1Passord and I made sure the web page URL is saved correctly. Instead of seeing my username above the keyboard as it should be, I see "[Key Symbol] Passwords".
It used to work correctly, ie, it would fill in the user name and password without directing me to the 1Password app. Something has changed, but I do not know what!
1Password Version: 7.3.3
Sync Type: Families subscription
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
Sync Type: Not Provided