Clothing in The Division are purely cosmetic apparel for the player to wear. Most of the clothing item you find will be from assisting civilians that are in need by giving them their wanted resource. Other times you can find clothing in various apartments if you explore the world more, for example in a clothing closet of an apartment. Lastly, you can also obtain more clothing items from drops inside the Dark Zone. To view what clothing items you currently already obtained, all you have to do is check the apperance tab of your inventory screen. You can view your available clothing in the Appearance tab of your Inventory screen.