This trophy is called "Refashion" and it requires the user to change the appearance of an item via Refashion at the Blacksmith.
To reach the Blacksmith, the user first must complete the Tower of London prologue and then the first mission, "Isle of Demons."
Once Onryoki has been defeated in Isle of Demons, and you have been brought to the Kyushu Region Map, select "Starting Point" to find the Blacksmith Tome. Select the Refashion option in the middle of the list and select either Weapon or Armor. You can select a common (white) item in "Item to Refashion" and then anything from the list in "Appearance to Copy." Once both slots are filled, scroll down to Refashion and unlock the trophy.