If you are looking to connect ClickFunnels to your Gmail account, the best way is going to be by using Zapier.
Zapier already has several free Zaps that you can check out here.
Additionally, you may want to read this article on how to increase your Gmail open rates when sending emails through SMTP.
Also, if you haven’t yet invested in ClickFunnels, I would highly recommend checking out the Funnel Hacks special offer.
Funnel Hacks is the only deal or discount that exists for ClickFunnels and will not only save you hundreds of dollars on your ClickFunnels membership, but will also give you access to some incredibly valuable bonuses that will help you make a ton more money with ClickFunnels if you actually use them.