Thank you for contacting us. Passkeys that are stored either from a different password manager or stored in mSecure are unable to be shared between applications currently. This may be different in the future, but for the time being, this is unable to be shared. I'm sorry for the inconvenience this may be for you.
Christopher
I use both the Apple Passwords app and the mSecure app on my Mac mini, iPhone and iPad. I often copy passwords generated by Apple Passwords in mSecure (to have more than one copy). Can I do this with passkeys? If so, how do I do it, please?