An HOA board gets elected by owners in a homeowners association to manage the affairs of the HOA. They will enforce the CC&Rs, oversee the property manager or – if none is appointed – directly handle the maintenance, repairs, insurance, and owner communication. They typically meet between AGMs on a monthly basis, sometimes with holiday or seasonal breaks. Any owner can apply to join their condo or HOA board.
It is important to remember that HOA board members are volunteers and essential to running a successful community. If nobody volunteers, everything stops – no bills will be paid, no maintenance will be done, eventually creditors will file suit to be paid and the court may appoint a receiver to run the association. Now some stranger is running the association and you the owners are paying $500/hour for him/her to do so.