When carrier delivers cars and completes the job, they will be asked to upload a picture of BOL and they can also mark the job as delivered.
When you will need to pay a carrier, after completing a job.

As you get all of the required documents from carrier to start processing a payment to them, you can mark the job as Invoice Received.

This will start the payment cycle for the carrier and the system will notify you if the payment is Due or Past Due to carrier.