Family sharing for keychain
How to share passwords stored in Keychain across Family Sharing devices
iPhone 13 Pro, iOS 15
Question marked as
There is no means to automatically do that with Apple Keychain (sharing which’d also be a serious mess for many of us), though you can share iCloud Keychain passwords manually using AirDrop, and similarly sharing Wi-Fi passwords, and sharing by third-party password managers that can provide that.