You can screen share during a call by following the steps below:
Click on the More (three dots) option once you have initiated the call.
Select Start screen share from the options.
You will have the option to share a tab from your browser, Window or the Entire screen.
Note: If you share your screen for the first time and your Chrome version is 71 or below, you will have to install the Zoho Cliq extension. For chrome versions 72 and above, the extension is not required.