This is also known as a debt certificate. It is a bond that is not listed on a stock exchange. Debt securities are issued by companies and governments and can be executed under different conditions. For the government, these papers are issued as government bonds.
Debt securities allow companies and governments to borrow money. It is generally accepted that government bonds are safer because the government is believed to be better able to service debt. It entitles you to (usually) a fixed interest rate and the investment amount is repaid at the end of the term.
