Try actually sending the e-mail (you do need to use Apple Mail for this feature). Once you hit "Send" you should get the Maildrop suggestion.

On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.