In a heavy-equipment workshop the job card is where cost is captured: parts issued from the store, technician time and outside services are all charged to it. Comparing that cost with what is invoiced shows the profit on every job.
Job cards also build the service history of each machine, which supports warranty claims and maintenance planning.
How Civova handles it
In Civova every workshop job card is a cost centre: parts at FIFO cost, technician hours and outside work are charged to it, and the customer is quoted and invoiced against it.