The Congressional Research Service (which exists to help Members of Congress to be informed about the world and itself) has a report on this topic, called Congressional Salaries and Allowances: In Brief. The text is available at the link below.https://www.senate.gov/CRSpubs/9...Every Senator and Representative gets an annual salary plus an allowance for doing the work of representing their constituents, like maintaining offices in DC and at home, communicating with and serving constituents, traveling back and forth to DC, and developing legislation.If you are asking how much a Senator can spend for travel and meals while on official business, each house allocates an annual amount for those expenses and the Member has flexibility in how to use those funds.