During your time in Prey you can use Talos I's security systems to eliminate your enemies. To be more precise, you can use turrets for that. In default they are hostile only towards Typhons but if you want them to attack, e.g. people then you can use Hacking II ability and reprogram them.
The game also allows you to move them. They are rather light which is convenient and it means that you don't have to spend neuromods to unlock Leverage abilities, unlike with other, heavier objects. When you place a turret (the best places for that are narrow corridors or near an exit from a room) you can attack enemies and let them come closer to your turret so it can fire at them. This is a good method for dealing with Mimics and other weaker opponents (e.g. humans with overtaken minds). When it comes to stronger Typhons, and the fight is one-on-one, the Typhons wins almost all the time. In those situations turret's role is changed - you can use it to distract a monster which allows you to attack it easier when a monster is not expecting that.
A big problem with relying on turrets is that, in default, they are very weak. If you place them in a wrong place or if they are attacked by stronger enemies they can be easily damaged and will stop their fire. Fortunately, you can upgrade them although this process is very limited. When you unlock Repair III human ability you can fortify them so they can last longer and withstand more attacks. But because this operation requires you to use a few spare parts you should do it only when a given turret can be useful to you or when you move them between main areas and puts them in different places on the map.
Luckily for you, turrets are very rarely destroyed by enemies. In almost all of the cases a turret, when it loses all of its energy bar, simply turns off. When this happens you can decide to fix them but your Repair ability must be at least on level II and you also need spare parts in your inventory. But don't waste your spare parts on fixing absolutely every turret because once you use the materials to fix (or fortify) a turret you can't get them back.
Warning - If you are constantly lacking spare parts you should think about unlocking Dismantle human ability. It allows you to get spare parts by dismantling equipment in your inventory (but use it only to get rid of useless things!) and when you are examining operators' remains (you can also destroy them by yourself if you are absolutely certain that they won't be useful to you in a given area or when a nearby operator dispenser allows you to order new machines to replace the destroyed ones).