Re: How do you delete contacts from your I Phone 6s using I cloud on your Pc?
Welcome to iMore! Make sure that the contacts on your device are assigned to the iCloud group. Open the Contacts app, then tap on "Groups" in the upper, left hand corner. Hide any group that you don't use, which generally means that "All iCloud" will be the only group checked. Also check in Settings > iCloud and make sure that Contacts are enabled. If everything is set up correctly you should be able to use icloud.com to manage your contacts, including deleting existing ones.
Keep in mind that contacts in your phone may not sync immediately after they're updated on icloud.com. This may take some time.