How do I enter cross-beamed eighth notes in Finale?
In case the link https://www.finalemusic.com/blog/finale-quicktips-cross-staff-beaming/ dies:
Finale QuickTips: Cross-Staff Beaming
Write all of your notes for the cross-staff passage in one staff.
Choose the Selection tool then click and drag to select the notes you wish to move.
After you have selected the region of notes you wish to move, press ALT+SHIFT+Up/Down Arrow (Win) or OPTION+SHIFT+Up/Down Arrow (Mac). (*no shift in Finale 2014 or later for Mac)
You can then use the Beam Angle tool from the Special Tools palette (Window > Special Tools Palette) to alter the beam height and angle.