Can I remove mold myself?

Sometimes. A small spot on a hard, already-dry surface — tile, glass, sealed wood — can be washed with detergent, dried, and left alone if the leak is fixed and nobody in the house is medically fragile. Wear gloves and at least an N95, and do not run the HVAC fan.

Do not DIY drywall, insulation, a crawl, or anything inside an air handler. Do not bleach a basement wall as a substitute for removal. If the spot is bigger than about ten square feet or it returned after cleaning, hire a crew with containment.