Hi Janardan,

Please see this guide, specifically the Q&A, from Vesa at Microsoft: Automating add-in/app installation to SharePoint sites using CSOM – Vesa "vesku" Juvonen 

Add-in/app which being installed has to be pushed by uploading app file directly to the site where it’s being added

• You cannot push add-ins/apps from the store or from the app catalog to the sites

Q&A

Can I automate app/add-in installation for apps in the SharePoint store?

No. This is not possible, since store apps have licensing implications, so they cannot be just installed using simple API calls.

Unfortunately there is no way to do this with a Store App, this is by design of SharePoint Online/SharePoint Store.

Thanks,

Callum