Governments use some tax revenue to pay people who work for the government and to transfer income to those living in poverty. In exchange for the work they do as government employees, workers expect to receive payment in the form of wages or salaries. These public goods are used by households. Saving is income that isn't spent on current consumption or taxes. Households earn interest on their savings.
Financial institutions lend money that is on deposit to businesses.
Businesses use this money to invest in capital goods with which they may build new factories or buy new tools and equipment. Businesses pay interest on these loans.