How to delete iCloud Contacts
Before deleting all contacts, it's a good idea to have a backup. If you accidentally delete something important, you'll always have the option to restore it later. Please follow this article about How to export iCloud Contacts in order to make a backup.
Follow these steps to delete iCloud Contacts:
Step 1. Open your browser and go to www.icloud.com/contacts. Login to your iCloud account if necessary.
Step 2. In the Contacts window, you can select multiple contacts at once. Hold down the CTRL button on your keyboard whilst clicking on the specific contacts you want to delete.
Or, select a single contact in the list and then press the CTRL+A keyboard combination to select all contacts.
Step 3. Once the selection is made, click the Gear icon in the bottom-left corner of the page and choose the Delete option from the menu.
Step 4. Once deleted, click the Gear icon in the bottom-left corner of the page once again, and now choose the Refresh Contacts option from the menu.
Step 5. Once refreshed, some of the contacts may return to the list. Refresh the iCloud Contacts webpage in your browser to check if your contacts were deleted successfully. If the issue persists, repeat the above steps once more.