Put it into a waxed paper sandwich bag, box, or aluminum foil. Tree associations may be important, so slip in a sample leaf, cone, or branch from nearby plants. Slide in a note with your name, phone number, collection date, and county where the collection was made. That will help the identifier gather information about unusual finds. Finally, don't expect names for everything.
Some mushrooms take hours to name.
Others can't be named at all. Collecting for the Pot Collect only mushrooms you can positively identify. Pick only those in choice condition and leave those past their prime to distribute spores for next year's crop. The limited studies to date indicate that neither method is better for the mycelium. In either case, cut off the stem cleanly and brush off as much soil and debris as possible.