The Controlling module in SAP provides management with supporting information for planning, reporting, and monitoring business operations. It includes components like cost element accounting, cost center accounting, internal orders, activity-based costing, product cost controlling, profitability analysis, and profit center accounting. Maintaining controlling areas and number ranges are important setup steps in the Controlling module configuration. A controlling area can include one or multiple company codes that use the same chart of accounts. Number ranges need to be defined for controlling documents like cost centers, internal orders, and product cost estimates.