Hi Amit,
Screen sharing is available and is free to use during any video conference. You will see the option show up once you are already in a conference. You can also test it out without having anyone else in the call.
I have updated the help documentation with a step by step guide with lots of screenshots to help you get started.
Checkout the screensharing guideQuick Summary:
Start your video conference from the blue phone on the right, once started hover your mouse over your video or image and a blue icon that looks like a screen will appear, click that to add your screen to the conference.
Note: Screen sharing is only supported in Google Chrome for the moment, and requires you to install an extension from us. Once installed remember to start screen sharing again.
Goodluck!