If you’re still trying to get iOS 12 installed and running sweetly, you might check the Mac App Store for updates: Apple has just released the latest version of Safari for macOS, version 12.0.
This includes automatic suggestion of strong unique passwords when creating a new account with a service, or changing an existing password. It will also indicate any passwords which you have re-used. It adds the ability to block specific popups, and has other improvements.
There are three security fixes too, which include recently-revealed user interface spoofing which could be used to hijack you to a malicious website.
Safari 12.0 is available now for macOS Sierra 10.12.6 and High Sierra 10.13.6, and will be included in Mojave 10.14 when it ships next week.