//MARK: Contacts

    func checkContactsStatus() {
        let status = CNContactStore.authorizationStatus(for: .contacts)
        if status == .denied || status == .restricted {
            presentSettingsActionSheet()
            return
        }
    }

   //Ask for Contact Permissions
    func presentSettingsActionSheet() {
        let alert = UIAlertController(title: "Permission to Contacts", message: "This app needs access to contacts in order to ...", preferredStyle: .actionSheet)
        alert.addAction(UIAlertAction(title: "Go to Settings", style: .default) { _ in
            let url = URL(string: UIApplicationOpenSettingsURLString)!
            UIApplication.shared.open(url)
        })
        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel))
        present(alert, animated: true)
    }

    func contactPicker(_ picker: CNContactPickerViewController,
                       didSelect contactProperty: CNContactProperty) {

    }

    func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
        // You can fetch selected name and number in the following way

        // user name
        let userName:String = contact.givenName
        let surName:String = contact.familyName
        let fullName:String = userName + " " + surName
        print(fullName)
        contactTextField.text = fullName

//         user phone number
//        let userPhoneNumbers:[CNLabeledValue<CNPhoneNumber>] = contact.phoneNumbers
//        let firstPhoneNumber:CNPhoneNumber = userPhoneNumbers[0].value

        // user phone number string
//        let primaryPhoneNumberStr:String = firstPhoneNumber.stringValue
//        print(primaryPhoneNumberStr)
    }

    func contactPickerDidCancel(_ picker: CNContactPickerViewController) {

    }

    func chooseContact() {
        let contactPicker = CNContactPickerViewController()
        contactPicker.delegate = self
        contactPicker.displayedPropertyKeys =
            [CNContactGivenNameKey
                , CNContactPhoneNumbersKey]
        self.present(contactPicker, animated: true, completion: nil)
    }

Info.plist

<key>NSContactsUsageDescription</key>
<string>This app requires contacts access to function properly.</string>