Harmonics
String harmonics are often notated as a diamond or small circle above the notes they affect. In Finale, you either create the harmonic symbol as an articulation or change a notehead on the same stem.
For instructions on creating, moving, and deleting articulations, see Articulations. For instructions on changing a notehead to a diamond shape, see Document Options - Notes and Rests. See also Easy Harmonics Plug-in.