Do treasury securities finance a federal budget deficit? If so, would the government purchase treasury securities to finance the budget deficit or would they sell them?

When there is a federal budget deficit, the government must finance the excess spending by borrowing. One way to borrow is to issue treasury bonds. In general, a bond could be viewed as a borrowing-lending contract between two parties, with the issuer acting as borrowers and the buyers of bonds acting as lenders. Therefore, to finance the budget deficit, the government will issue treasury securities.