There are lots of platforms available to help you send out marketing emails. Our personal favourite is Mailchimp, however other platforms are also available. Check out Constant Contact, Get Response, Campaign Monitor, Hubspot and StampReady if you want some well-known alternatives. Many customer database / CRM software packages now include some form of email marketing client in as well so it may be cost-effective to explore this option. We design all our emails in HTML so they can be used across any platform.