Hi @vijendra258,
A new site has to have an administrator, and that is how core WordPress works when a new user registers a site, even if the Cloner is not installed. The new user will only be an administrator for their site, not other sites on the network or the network itself, so their permissions are localized. If there’s certain things you don’t want users to be able to get to you may want to research a roles / capabilities plugin to change what administrators (regular ones, not super_administrators) can do.
Hope this helps.