From the Summary: "Under the U.S. Constitution, Congress exercises the 'power of the purse.' This power is expressed through the application of several provisions. The power to lay and collect taxes and the power to borrow are among the enumerated powers of Congress under Article I, Section 8. Furthermore, Section 9 of Article I states that funds may be drawn from the Treasury only pursuant to appropriations made by law. The Constitution, however, does not prescribe how these legislative powers are to be exercised, nor does it expressly provide a specific role for the President with regard to budgetary matters. Instead, various statutes--as well as congressional rules, practices, and precedents--have been established over time to create a complex system in which multiple decisions and actions occur with varying degrees of coordination. As a consequence, there is no single 'budget process' through which all budgetary decisions are made, and in any year there may be multiple budgetary measures necessary to establish or implement different aspects of federal fiscal policy. This report is intended to describe in brief each of the parts of the budget process, discuss the role of Congress in each aspect, and explain how they operate together. They include the President's budget submission, the budget resolution and reconciliation, the authorization and appropriations process, and budget enforcement and sequestration. In addition, this report provides a flow chart of congressional budgetary actions."
CRS Report for Congress, R46468
Congressional Research Service: https://crsreports.congress.gov/