please explain the silver upgrade facility obtained

Sorry, but could you explain what exactly is your question?

Are you looking at upgrading to the Silver plan? If yes, please check this related guide: https://www.jotform.com/help/331-How-to-Upgrade-My-Account.

You can check the Silver plan features on this link:https://www.jotform.com/pricing 

If you are referring to something else, please let us know.