How to Sync Google Contacts & Groups to Your iPhone
Unless you want to occasionally waste time hunting for information on a device other than the one you're currently using, syncing your contacts between your Google account and your iPhone is a necessity. Once the sync is set up, the information in your Google contacts will be an exact mirror of the one in your iPhone's Contacts app, and vice versa.
1 Setting Up the Sync
If you have already set up your Google account in your iPhone, syncing your contacts is simply a matter of flipping a virtual switch. Open the "Settings" app, tap "Mail, Contacts, Calendars," tap your Google account to display the options for it and ensure the switch labeled Contacts is set to "On."
If you've yet to set up your account, it'll take slightly longer. Open the "Settings" app, tap "Mail, Contacts, Calendars," tap "Add Account" and then tap "Google." Fill in your account information, tap "Next," ensure the Contacts switch is set to "On" and then tap "Save."
Either way, once contact sync is active, simply open the "Contacts" app on your iPhone to trigger the sync. From now on, any contact you create or modify on your iPhone will also appear in your Google contacts and vice versa.
2 Article Disclaimer
Information in this article applies to iPhones running iOS 7. It may vary slightly or significantly with other versions.