Harvey Robert Appel, 67, motion picture distributor, died June 20 after a long illness.Appel, who was a Boston-area distrib for 25 years, was also longtime branch manager for American Intl. Pictures. He served as president of NFB Film Distributors from 1976 until his retirement. Survived by his wife, Rita, two daughters, a son and three grandchildren. Donations may be made to the Multiple Sclerosis Society or to the American Cancer Society.