The Bill of Lading is an important document used throughout the import process. The first role the BOL plays is a receipt, handed to the seller(by your freight forwarder) as proof that the seller handed over the goods in good condition. The second role the BOL plays is a shipment contract indicating (on the reverse side) the terms and conditions of the forwarder.
The master BOL number is also useful in shipment tracking, and the BOL usually includes other tracking identifiers like container numbers. If you pay your seller via Letter of Credit, you will need to include the bill of lading. The same case applies when filing claims for lost or damaged cargo.
Usually, suppliers will ask you if you prefer the original bill of lading or the telex option. Asking for the telex bills of lading is the best option because it reduces the risk of losing the original BOL as it travels via post. However, if you pay via a letter of credit, the supplier might insist on sending the original bill of lading. If you have the original document, you will need to present it to customs upon the arrival of your goods to have them cleared.