Agent Simmons

Real Name
Jemma Simmons

Occupation
S.H.I.E.L.D. Xenobiologist

Citizenship
British

Place of Birth
United Kingdom (assumed)

Known Relatives
Mr. Simmons (father), Unnamed mother, Unnamed brother and sister

Group Affiliation
S.H.I.E.L.D.

Education
University Graduate

Height
Unrevealed

Weight
Unrevealed

Eyes
Brown

Hair
Brown

Powers 
None

Abilities
Skilled Xenobiologist

Other Info 
Jemma Simmons is the daughter of a high level Roxxon executive. (To learn about Roxxon, click on their name above.)

Later on, Jemma Simmons joined S.H.I.E.L.D. and made her parents believe she was a party planner. 

At one point, Agent Simmons was one of the S.H.I.E.L.D. field agents who was recruited to form Agent Phil Coulson's team to investigate how the terrorist Abu Mussan got hold of Heimdall's Uru sword. Along with Agent Melinda May, Agent Simmons helped Heimdall break free from Mussan's terrorist group. After Heimdall was dispossessed from the influence of an alien rock, Simmons recovered fragments of the alien rock to investigate on the S.H.I.E.L.D. Helicarrier. (Click on the highlighted names above to learn about the team, characters, material, and/or vehicle.)

There is nothing there, but here is the Marvel.com bio page of Agent Simmons, http://marvel.com/universe/Simmonds,_Jemma.

The "Jemma Simmons" character was one of the only Marvel characters that did not originate in the comics. Agent Simmons first appeared in the TV show, Marvel's Agents of S.H.I.E.L.D. It wasn't until 2015 that Agent Simmons entered into the main Marvel comics universe (Earth-616) in the comic books alongside many of her fellow Agents of S.H.I.E.L.D. cast members.