# Core Concepts ## Core Concepts These terms appear across travel, expense, and approval workflows. ### Key terms * **Travel Request** — A pre-trip request for review and approval. * **Expense** — A reimbursable or company-paid business cost. * **Receipt** — A supporting document used for review and auditability. * **Budget** — A spending limit for a department, project, or function. * **Cost Center** — A coding value used to allocate spend. * **Approval Workflow** — The review path a request or expense follows. * **Policy Validation** — A check against business rules and spend policy. * **RBAC** — Role-based access control for pages, actions, and data. * **Multi-role access** — Access that reflects more than one responsibility. * **Unified dashboard** — A shared workspace for current tasks, alerts, and status. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.techzala.com/introduction/core-concepts.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.