One thing that I really like about Borderlands 3 is that you get your own room on Sanctuary to decorate however you see fit. It's a neat idea and I can't tell you how many times I've wished other loot-based co-op games gave you some space to create your own.
Where to find your room
Your room is located at Sanctuary Reading, right next to the fast travel point and the lost loot machine.
How to decorate your room
There are a few empty hooks on the wall that will allow you to place decorations if you approach them and press the interact button. There are three hooks in total, but one of the spots is quite dark, you might want to put a neon sign there. There is also a row of panels on one of the walls that will allow you to place a weapon or equipment. It's really nice because the weapon hangs on the wall, and the outside of the panel will glow with the rarity of the weapon's colors. It's a very cool way to show off your awesome legendary and epic weapons.
How to get decorations
While any weapon can be placed on the panels, you can get decorations for the walls by opening chests, completing missions, and purchasing them from Crazy Earl. You might be better off saving Eridium for weapons and such, and letting cosmetics be your own personal focus when you already have a ton of cool guns, but that's your choice.
And there you have it, everything you need to know about your bedroom and its decoration.