The hired workers are computer-controlled players that can help your farm at the cost of money. They drive and use the vehicle and most of the tools that can be used by the chosen vehicle. Hired workers will not consume fuel in the vehicle tank nor consumables for the implements such as seed or fertilizer but rather purchase all of these things in real time as the worker would need them.
Note: The worker will only use the vehicle that you hired them on. Also, the workers will only use certain machines and implements. Stuff like baling, fertilizing, mowing or selling your harvest will have to be done by the player.