When you have contacts from multiple sources, you might have multiple entries for the same person. In the Contacts app, link contact cards for the same person in different accounts so they appear only once in your All Contacts list. Linked contact cards are displayed as a single unified contact.
If you have more than one contact card with the same first and last name, the Contacts app can merge the duplicate contacts for you.
Go to the Contacts app Add and use contact information on iPad