A debenture is a small to a long-term format for debts that is made by big companies for borrowing money. These are more like common long term based loans that a company could take. These debentures happen to be loans that can get repaid by a fixed date.
The holders to debentures carry no rights to vote in the general meetings of the shareholders however they can attend separate meetings or make seperate votes. Investors can benefit from debentures as they can get sold in stock exchanges and carry lesser risks as compared to equities. Hence, they happen to be far more suitable for individual investors.