Workflow: Used to manage document approvals. A purchase requisition requires a structured approval path (e.g., manager approval) based on specific conditions like monetary thresholds ($50).

Audit policy: Used to evaluate expense reports and vendor invoices for compliance with business rules. While workflows handle the routing of documents, Audit policies are specifically designed to "review" or "enforce compliance" by automatically flagging exceptions—such as offsite travel expenses that violate company limits or vendor invoices that don't meet duplicate or tax requirements—before or after the document is processed.

Microsoft Learn: Workflows in Dynamics 365 Finance and Operations. Provides details on using workflow for purchase requisition approval processes. (Section: "Workflow system overview").

Microsoft Learn: Audit policies in Dynamics 365 Finance. Explains how audit policies are used to evaluate expense reports and vendor invoices for compliance with business rules. (Section: "Audit policy overview").

Microsoft Learn: Set up Expense management. Details how audit policies specifically target expense categories like "travel" to identify non-compliant entries.

Official Training Material (MB-300): Core Finance and Operations. Module on "Configure and manage business processes," specifically differentiating between approval routing (Workflow) and compliance validation (Audit Policy).