It has the capacity to hold hundreds of personnel
The ship is armed with nuclear warheads, propped with multiple dropships from planet landings. It also has an automatic escape system where the hyperspace pods are moved to a chunk of a ship which ejects in case of fire.
The Sulaco was dispatched to investigate communication loss of the colony of Hadley's Hope on LV-426. Though it could carry hundreds, it only delivered a small squad to LV-426. The head of the squad, Lieutenant William Gorman, was the head of the operation despite little experience in the field. The team was accompanied by Ellen Ripley, sole survivor of the Nostromo disaster involving a Xenomorph encounter. The mission that the squad was on didn't go as planned, they had numerous encounters with Xenomorphs that cost the lives of most of the crew until only Ripley, colony survivor Newt, android Bishop, and remaining Marine Hicks. Hicks was badly injured by acidic blood and Bishop was torn in half by the Alien Queen who snuck on board.