Automagically creating strong passwords

If not on:

1. Go to Settings -> Passwords -> Password Options.

2. Turn on AutoFill Passwords.

Next time you create an account in an app or at a website, when you select the Create password field, you’ll see iOS has automatically inserted a unique password in the field. Tap the Use Strong Password button to use the recommended password, and iOS will automatically store it in your Keychain. iOS never generates the same strong password twice.