In PMWeb, a contract is defined as an agreement between you and your client. Contracts are used to track revenue and are modified and extended using these PMWeb record types:
Each line in a Contract record and Contract COs automatically becomes a "Req Code". Lines from other types of transactions (such as Progress Invoices and Timesheets) can be linked to these Req Codes. These cost based lines can then be automatically pulled into Requisitions, allowing you to perform cost plus type billing scenarios.