Think of a government budget like a household budget, but on a massive scale. It's a plan detailing expected income (revenue) and planned spending (expenditure) for the upcoming year.
A government budget is an annual financial statement that presents the government's anticipated revenues (from taxes and other sources) and proposed expenditures for a fiscal year. It is a plan for how the government will spend its money and how it will pay for its activities, reflecting the government's economic and political priorities.