Starfleet Security are responsible for the protection and overall safety of their posting and everyone on it, as well as members of away teams and civilians on colonies. They have a close working relationship with Starfleet Tactical, Starfleet JAG Corps, as well as FedSec, upholding both Federation law, as well as Starfleet's own codes of conduct and protocols, should it be necessary.
While some positions are listed below, this is not the definitive list and there are plenty of other positions your character could have. We encourage creativity so be sure to chat with admins if you have any ideas! Please note that all Security officers have response training and the ability to respond to an emergency should it be needed, but officers with specific assignments usually won't leave their posting unless absolutely necessary.
A Patrol Officer does as the name implies: They patrol. But to be specific, their job would entail anything from patrolling their posting, responding to security incidents, as well as guarding key locations during Yellow or Red Alert.
A Brig Officer is responsible not just for guarding the brig, but for the welfare of those in it. Detainees are fully within their care, and as such must remain vigilant should anything arise.
A Transport Guard is responsible for guarding transporter rooms, as well as shuttles and other transport ships.
Security Systems Officers are responsible for monitoring the security systems of their posting, be it security cameras, security sensors, or anything else that could alert the Security division to an incident or emergency.
Just like in the 21st century, Investigation Officers investigate crimes that have been committed, be it on their posting or nearby, working closely with FedSec should the incident involve persons not in Starfleet.
A Crisis Negotiator is an officer trained in deescalating and resolving crisis situations, including hostage situations and even mental health emergencies if a mental health professional isn't available to respond. They are highly empathetic individuals who put themselves mentally in the person they're talking to's shoes to understand their reasons and come to a level of mutual understanding with them, with the aim of preventing things from continuing down the path they are on.
A Phaser Specialist has advanced training and knowledge of phasers, and is highly skilled in their ability to use one. They are frequently sharp shooters, capable of hitting a target at long range if needed.
A Master at Arms is responsible for maintaining Security's equipment, especially phasers. They work closely with Tactical officers in the armoury to make sure, should they be needed, all Security officers equipment will not fail them.
Health and Safety Inspectors are responsible for making sure their posting is up to code in every way, including but not limited to structurally, systems (such as fire suppression and life support), food standards, and general hygiene. They are indirectly responsible for the welfare of every living being on their posting, including people and animals, and work closely with the Federation Occupational Safety and Health Administration, the Federation Food Standards Agency, and the Federation Society for the Prevention of Cruelty to Animals. They have been known to seize animals should its owner be breaking animal welfare laws.