This simple app is about exploring the necessary parts to allow an app work with autofill, i.e. the iOS keyboard automatically suggest the required information to fill in.

Feature description:

• suggesting existing passwords stored in the keychain to sign-in
• suggesting a strong password to use when signing up.

To implement this feature I had to do the following steps:

1. Add "Associated Domains" capability and set "Domains" to webcredentials:example.com (replacing example.com being my domain).

2. On the website place a file named apple-app-site-association into the publicly accessible root directory in a folder .well-known.
   Access can be tested using curl https://www.example.com/.well-known/apple-app-site-association. (Yes, HTTPS must be enabled and have a valid certificate!)

3. The content of the apple-app-site-association must reference the Apple Developer Team ID and the bundle identifier of my app as follows: (Team ID is "A1BC23REUG" and bundle identifier is "com.example.signin-playground")

   {
     "webcredentials": {
       "apps": [ 
         "A1BC23REUG.com.example.signin-playground"
       ]
     }
   }

4. Mark the input fields in SwiftUI using the appropriate textContentType modifiers: .username, .password and .newPassword.

Feature description:

• intelligent completion based on information from the address book or recent usage of other apps

To implement this feature I had to amend the TextFields fields with the appropriate value for the textContentType modifier. But some of the fields have never shown an appropriate suggestion.
These are: .namePrefix, .nameSuffix, .middleName, .nickname, .organizationName, .jobTitle, .location