Passkeys & WebCredentials
Associate your app with your domain for Passkeys and Password AutoFill.
WebCredentials associate your app with your domain for Passkeys and Password AutoFill. When configured, iOS can suggest credentials for your app that were saved on your website, and vice versa.
Configuration
Add your App ID in the Password AutoFill / Passkeys section under Associated Domains.
Xcode setup
Add the Associated Domains capability with webcredentials:your-domain.com.
Custom domain required
Passkeys and WebCredentials require a custom domain. Configure one in Custom Domains.
Apple reference: Connecting to a Service with Passkeys