Lockpick is one of the gadgets in the Shadow of the Tomb Raider. The item is required for opening chests (a category of secrets). Lara doesn't have any lockpicks by default. This section will let you learn how to get the Lockpick in the Shadow of the Tomb Raider and how to use it.
You can buy the lockpick from Moraekah in the Hidden City Paititi. The best idea is to go to her during the Dice with the Dead quest, after being ordered by Pisco the Dead to find the remaining exiles. One of the people you have to question is Moraekah, whose location you can see above. Apart from progressing in the quest, you will also be able to trade with Moraekah.
Moraekah will change her location a few Times during the game - more info on that can be found in the "Where do I find Moraekah the merchant?" section of our guide.
The Lockpick is one of the items sold by Moraekah - it costs 2800 gold (the picture above). Lara only one lockpick and she will never lose it.
Once you have the lockpick, you will be able to open the treasure chests. Once you find one, just press the contextual button and Lara will simply open the chest (see above).
Note - Treasure chests can be found in some locations you visit before being able to buy the lockpick, such as Cozumel and Peruvian Jungle. You should go back to these locations in order not to miss any secret.