Can I Copy A Passkey From Windows 11 To 1Password?

While theoretically possible, migrating passkeys between platform safely and securely is still in the planning stages, so not yet practical.

Until a safe and secure method is available in the clients, you should add passkeys for each client to each service, i.e. you'd have both a Microsoft passkeys and a 1Password passkey. If you no longer want the Microsoft passkey, then remove it from the service and the client after successfully testing the 1Password passkey.