The secondary market acts as a marketplace to trade in securities, funds and financial assets post their launch in the primary market.
Among the various instruments traded in the secondary market, a few are mentioned below:

A share is a unit of ownership, equivalent to the value of the share, that companies give to their shareholders. Investors can buy & sell these shares at a stock exchange such as NSE & BSE. There are a total of 23 stock exchanges in India, of which these two are the most active.
Bonds are basic debt securities traded in the debt market. Companies issue bonds to raise capital, giving a regular coupon payment to bondholders along with a fixed maturity.
Mutual funds are professionally managed funds that invest in certain stocks with a common investment goal/objective. The mutual fund market has shown rapid growth in the last few years. There are various types of mutual funds such as Equity, Debt, Hybrid etc.