Equip Weapon Trinkets
That said, now that you collected a trinket, the game doesn’t explain how to equip one of these. To equip a weapon trinket, open up your menu and go to your backpack inventory. Here, you can equip the guns that you are carrying. If you look to your equipped weapons, there is a small empty box to the left of them. By navigating to it, this will open up a new window on the opposite side of the screen with your collection of trinkets. Select one of the trinkets and it will show up on your gun when you use it in the game.
How to get Weapon Trinkets
At the beginning of the game, you won’t have any weapon trinkets. There are 3 ways to how you can get them. Trinkets are part of the loot system in Borderlands 3, so they can drop from enemies or show up in chests. Bosses can drop legendary trinkets or you get them as a quest reward. Another way to get weapon trinkets is to shop at Crazy Earl on Sanctuary 3. He will sell you various cosmetic items for Eridium.