HOW TO MERGE AND REMOVE DUPLICATE GOOGLE CONTACTS

using the app for many years, your contact list is 

probably a mess, and although Google can not help you in determining 

whether you have any details of any person's contact, duplicate entries 

Identify and remove them.

You just need to follow the steps

first open Google Contacts  and Singne In Your Google Account

1 . click drop-down menu near the top left

2 . Click the "More" drop-down menu

3 .Click "Contacts" in the drop-down menu

4 .Click "duplicate" in the list and Click "Merge" when you're ready to merge the duplicate contacts.