How to specify a capacitor in Altium schematic as DNP
The correct way to do this is with variants, as others have pointed out. Do not use the 'Type' property. For every project I have a variant named "Only Populated Components" which makes it super easy to DNP components. Not populated components should NOT appear on the BOM, as this will indubitably lead to questions from the CM. They should also not appear on the PCBA assembly drawing.

A good sanity check to see what is populated and what is not is to view the PCBA in 3D; you can tell at a glance which components are missing.