A steward manages accomodation, dining arrangements, and provisions for a ship or station.
In the 23rd century ships' crews included stewards who worked in the galley, waited on the captain's table, and did other tasks like tidying and cleaning. They are enlisted personnel in the engineering and support division, under the command of a chief steward. (Star Trek: The Original Series, TOSS)
By the 24th century, replicators had become commonplace and officers generally waited on themselves. (Star Trek: The Next Generation, Deep Space 9, et al.)