Optionally convertible preferred share

These shares are corporate fixed-income securities that the investor can choose to turn into a certain number of shares of the company’s common stock after a predetermined time span or on a specific date. The fixed-income component offers a steady income stream and some protection of the investors’ capital. However, the option to convert these securities into stock gives the investor the opportunity to gain from a rise in the share price.

My question is how can we invest in ocps through Zerodha? or if not on zerodha where else can one get invested in ocps and how?

If it is listed on the exchange then you can buy it, check this post.