The Leather Working Tools in Red Dead Redemption 2 allow you to craft items early on in the game. By providing them to Pearson you can craft a number of different items. First you’ll need to unlock the Leather Working Tools by doing Camp Upgrades.
Once you’ve started earning money for the gang you will be able to contribute this cash to the gang’s reserves. Once you’ve got enough money in the gang’s bank you’ll be able to purchase upgrades for your different camp wagons.
The Leather Working Tools can be purchased with gang funds by using the Ledger. For all of the different camp upgrades, head here for the full list. Once you’ve got the Leather Working Tools upgrade purchased you will take it with you when the gang moves the camp.