To achieve resource-level visibility in cloud billing, the engineer should configure tagging. In CompTIA Cloud+ (CV0-004) objectives for cost management, chargeback/showback, and governance, tags (labels/metadata) are used to categorize and track cloud resources by attributes such as department, project, application, environment (dev/test/prod), owner, or cost center. Once consistently applied, tags enable detailed billing reports that break down spending per resource and per business unit, supporting accurate budgeting, accountability, and optimization decisions. Many cloud providers also allow ''cost allocation tags'' or similar features that integrate directly into billing dashboards and exports, making it easier to identify which workloads drive cost.

Rightsizing (A) is an optimization activity to reduce waste by selecting appropriate instance sizes, but it does not provide reporting granularity by itself. Invoicing (B) relates to billing documents, not categorization. Reserved instances (C) reduce compute costs through commitment discounts but do not inherently improve visibility into which teams or resources consume spend. Therefore, tagging is the correct configuration for resource-level billing visibility.