Darkness is your friend in Styx: Shards of Darkness, and the fact that there seem to be dozens of torches scattered about in each of the levels is something that can make your job a lot harder than it needs to be.
And although you can walk right up to them and extinguish them by hand, there is a way to accomplish this task from a distance, as well. Simply locate a bag of sand and collect some Pocket Sand (by pressing Y on the Xbox One or Triangle on the PlayStation 4), then equip it from your item wheel.
Now when you get a torch in your sights, Styx should automatically lock onto it, and a reticle should appear provided you’re in range. Pressing LB on the Xbox One or L1 on the PlayStation 4 should now make Styx throw the Pocket Sand at the torch, effectively putting it out.
Bear in mind though that although extinguishing torches can make it easier to sneak about, it can create other problems if you’re not careful. Extinguishing torches makes some noise, and if an enemy happens to be in proximity to one when it is extinguished with sand, they will become alerted and begin to investigate.