How to Delete All Contacts on iPhone through iCloud website
Step 1. Open the official iCloud website through any browsing engine on your MacBook or laptop. The website is www.icloud.com.
Step 2. On the very first page, you will be asked to login to your Apple ID. Enter your ID and your password.
Step 3. Once you are signed in, you will be redirected to a page containing the applications containing your data.
Step 4. Click on ‘Contacts,’ the first option you see, since it is here you want to make changes.
Step 5. The new page that opens up you will show you listed all your contacts.
Step 6. To select the contact you want deleted, press the ‘Command’ key and click on the contact. Since you want to delete all your contacts, select all the contacts this way.
Step 7. Once you are through with the selections, click on the ‘Command’ and ‘Delete’ keys on your keyboard. iCloud will ask you if you really want to delete all the selected contacts.
Step 8. Since you want to erase all your contacts, click on delete.
Step 9. This will remove all contacts. Wait for the changes to show up on your iPhone.
How to Delete All Contacts on iPhone Through your MacBook
Step 1. To delete contacts saved in your iPhone, open your MacBook and go to ‘System Preferences’. You will find it on the top left corner in the help bar.
Step 2. In the ‘Preferences’ window that pops up, select ‘iCloud’. It will be the first option in the third row.
Step 3. Once you do this, you will be taken to a new page where all the applications which can be synced to your MacBook will be listed.
Step 4. Here, make sure your Contacts are synced. Since the checkbox is filled, we can proceed.
Step 5. Now, look for the ‘Contacts’ application in your MacBook. If you can’t find it manually, you can run a search for it using spotlight. Open the application.
Step 6. To select a contact, click on the ‘Command’ key and click on the contact. Select all your contacts this way.
Step 7. To delete all contacts, press the ‘Command’ and ‘Delete’ keys simultaneously.
Step 8. Your MacBook will require you to confirm whether you want to delete all your contacts. On the pop-up window that shows up, click ‘Delete’ since you want to erase your contacts.
Step 9. Congratulations! All your contacts have been erased. Wait for a few minutes for the changes to show up in your iPhone.
How to Delete All Contacts on iPhone Reverting your iPhone to factory settings.
Step 1. Unlock your iPhone and find the ‘Settings’ application. It is the app with a grey icon.
Step 2. Click on it to open the ‘Settings’ page.
Step 3. On this page, scroll down to the third segment wherein you will see ‘General’ settings. Select this option.
Step 4. Doing this will take you to a new page where you can change all your systems settings.
Step 5. Here, look for the ‘Reset’ option. It will be at the bottom of the running page.
Step 6. Under the ‘Reset’ settings option, you will be allowed to format your phone to factory settings. This will automatically delete all your contacts. To continue, select the ‘Erase All Content and Settings’ option.
Step 7. Since this is a radical step, your iPhone will ask you for your confirmation. If you are sure you want to employ this method to erase all the contacts stored in the phone, click on ‘Erase Now’.
Step 8. Your phone will begin formatting and all your contacts will be deleted.