The most common mould you will see on bud is grey mold, or botyris. It is grey and powdery, and may have an 'off' smell.
You should not see it if you dry your buds quickly and completely. Spread them out in a cake pan or on a piece of paper, and set the pan in a warmish spot with some air flow. I like to put mine in the vicinity of a heating register, but not too close.