Tools of the Trade is the fifth quest in Act I of Diablo II: Resurrected. Players can pick it up by speaking to Charsi the blacksmith after they've completed The Forgotten Tower quest, or after entering the Tamoe Highlands, but only if they've reached at least level 8 with that character.
Tools of the Trade Diablo II: Resurrected Quest Guide
In the quest, Charsi asks that you retrieve the Horadric Malus. This enchanted smithing hammer used to belong to Charsi, but she was forced to leave it behind when she fled the Rogue Monastery before Andariel's invasion. Now, she wants it back so that she can use it to help the Sisters.
To get the Horadric Malus, you'll need to head to the Rogue Monastery. You'll find it by following the path through the Black Marsh and the Tamoe Highlands. When you make it to the monastery, head through the Outer Cloister into the Barracks. The Horadric Malus is hidden inside the Barracks, and it's guarded by a demon known as The Smith.
The Smith is a very powerful demon, and player may struggle to kill him at this early level. Luckily, they can complete Tools of the Trade without battling The Smith. They just need to grab the Horadric Malus and get it back to Charsi to complete the quest.
As a reward for returning the Horadric Malus to her, Charsi will imbue a piece normal equipment with randomly selected abilities. It's generally recommended that players save this imbuing for later in the game, as it can only be done once, and higher level items will yield more powerful results.