Hello Mistajames,
Thank you for participating in the Apple Support Communities! We understand that you're wondering how to add more than one email to your iPhone. Are both of the emails an Apple ID that you're trying to add or are you wanting to add the Gmail account to view emails in the Mail app?
If you're wanting to add more than one Apple ID, that is not currently supported. If you're trying to add the Gmail account in order to send and receive emails from this account, follow the steps here:
Add an email account to your iPhone, iPad, or iPod touch - Apple Support
Cheers.