Recordkeeping forms are preprinted with fields for specific applications, and are often backed with self-duplicating paper to create copies of the written record for both customers and businesses. Guest checks and receipt booklets can be used to record and verify payment. Purchase orders (PO) can be used to request goods and services. Invoice forms can be used to bill a customer for work completed. Bills of Lading (B/L or BoL) can be used to record the handling and transfer of cargo in shipping and receiving applications. Message pads, human resource (HR) and payroll forms, and petty cash forms can also be used to document interactions and operations in business organizations.