How to delete my account on icloud.com? In my case, I do not want to use iCloud anymore. So I don't want to sync notes, calendar, pics across my Apple devices, and access them through the web (i.e., icloud.com).

So, how I can close/delete my entire iCloud account, associated with my Apple ID? I just want to use my AppleID for the App store.
You can't remove iCloud from your Apple ID. The best you can do is clear information from it and not enable the iCloud services on your devices.