Sorry. I couldn’t figure it out by myself and don’t even know what it’s called.
Welcome to the forum, junsept97. You certainly can create notes like that in Dorico, very easily: use M to cross a note from the right-hand staff of the piano to the left-hand staff, or N to cross a note from the left-hand staff to the right-hand staff. See here for more information.
It worked. Thanks for your help, Daniel.