This wikiHow teaches you how to add contacts from your Gmail account to your iPhone's contact book. You can add a Gmail account if your account is not already on your iPhone or you can activate the contacts from an existing Gmail account on your phone.
Steps
Method 1 of 2: Add a Gmail account to Contacts

Step 1. Open the Settings menu on the iPhone

Press the Settings icon, which displays a gray box with gears.

Step 2. Scroll down and tap Accounts and Passwords
It's just below the middle of the "Settings" page.

Step 3. Press Add account
It's near the bottom of the page.

Step 4. Click on Google
You'll find this option in the middle of the page. Doing so will open the Gmail login page.

Step 5. Enter your email address
Enter the email associated with your Google account.
You can also use your phone number if it is associated with the account

Step 6. Click Next
It's in the lower-right corner of the page.

Step 7. Enter your Google password
Write it in the field in the center of the page.

Step 8. Click Next
Doing so will add your Gmail account to your iPhone and open the account settings page.

Step 9. Make sure the contacts are activated
If the button to the right of "Contacts" is green, everything is ready; if not, press the white "Contacts" button

to activate the contacts.

Step 10. Click Save
It's in the upper-right part of the screen. Doing so will save your Gmail account and add the contacts to your iPhone Contacts app.
Method 2 of 2: Activate Contacts from an Existing Gmail Account

Step 1. Open your iPhone Settings

Click on the Settings icon, it looks like a gray box with gears inside.

Step 2. Scroll down and tap Accounts & Passwords
It's in the middle of the "Settings page.

Step 3. Select an account
Tap the Gmail account from which you want to activate the contacts.
If you only have one Gmail account on your iPhone, click on "Gmail"

Step 4. Click on the white "Contacts" button

It will turn green

, which means that the contacts from the selected Gmail account have already been added to the Contacts application on the iPhone.
If the button is already green, Gmail contacts are already activated on your iPhone
Advice
If you have trouble importing your contacts, log into your Gmail account on your desktop. You may need to allow "login from unknown location" before continuing the import
Warnings
- Add a Google account to Contacts to add the Gmail calendar and other mail items to your iPhone. If you want to keep these options disabled, you can do so by pressing the green buttons on Mail and Calendar in the Gmail account settings section at Setting so that they go from green to gray.