The union budget is essentially the statement of the government's income and expenditure for the year. The ministry of finance consults with the government thing tank, nitti aoge and different spending ministries in order to arrive at the budget document. It details how much money the government expects to raise the next year and how it plans on allocating it among different states, departments and sectors. This year's budget is kind of a bigger deal than usual as India has had to deal with cowit and crippling lock downs these past two years.