Adding gmail into Mail from iPhone 6

Solution · On your iOS device, open Settings. · Depending on your iOS version, do one of the following actions: Tap Mail and then Accounts and then Add Account.

How do I set up Gmail on my iPhone?

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

1. Go to Settings > Mail, then tap Accounts.
2. Tap Add Account, then select your email provider.
3. Enter your email address and password.
4. If you see Next, tap it and wait for Mail to verify your account.
5. If you see Save, tap it.

Add an email account - Apple Support (IN)