I probably haven't used this command for over twenty years. It's hard to figure out how to use it effectively. As I recall, it is used in conjunction with the now undocumented PHYSICS command. Although undocumented, the PHYSICS command still works at 2022R1 (the most recent release I have tested). DAMORPH is probably not a good way to go if your objective is to simulate pull-in of a capacitively induced MEMS device (e.g., RF switch). For that, I would use coupled field PLANE223 with keyopt(1)=1001 and surface-to-surface contact elements with CNOF (contact normal offset) real constant to prevent complete closure of gaps (which would cause an element formulation error).
If you copy the following APDL into an input file and read that input file into MAPDL, you should have a working example of DAMORPH. Electrostatic and structural analyses are done sequentially (load vector coupling via LDREAD). The electrostatic mesh is then morphed via DAMORPH. A second sequence of electrostatic-then-structural calculations is made with the morphed mesh, and the electrostatic mesh is morphed again.