Sync Gmail contacts tp Ihone6

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Add an email account to your iPhone, iPad, or iPod touch

There are two ways you can set up an email account in the Mail app on your iOS device — automatically or manually. Learn which option is best for you.

https://support.apple.com/en-ca/HT201320

Hi,

Go to Settings ---Tap Accounts & Passwords Add Account----Enter your gmail email and password----Tap Next--

--Switch "Contacts" ON---- tap Save.