Kelly Chambers is the Yeoman/Administrative Assistant on the Normandy SR-2. Her primary job on the Normandy is to keep Commander Shepard abreast of new emails, pass on meeting requests from Shepard's squad mates, and keep the fish in the Captain's Cabin fed. In addition, Kelly provides counselor support and and monitors the psychological state of Shepard and the crew, offering input mission outcomes and impressions on Shepard's team.
If Shepard asks her about Cerberus' notorious reputation, Kelly refutes the notion that she or the organization is anti-alien. While she does believe in the importance of Cerberus' agenda to benefit humankind, Kelly doesn't believe that it means they hate other species by default. Throughout her time on the Normandy SR-2, Kelly regards aliens with the same respect and compassion she feels for her fellow man, evidenced by her repeated displays of concern over Shepard's non-human companions.
She is initially identified and titled as "Yeoman Chambers", but as you talk to and get to know more about her, it is changed to "Kelly Chambers" and is eventually referred to as "Kelly", possibly to show the growing camaraderie between Shepard and the crewmates.