Creating HTML rich email for Outlook

I have used mailchimp and constant contact for many years, but I have a request to create an html email that a customer wants to be able to send out one at a time (for follow up with customers).

Question is, where do I start, and how would they ‘import’ that into outlook? I am very comfortable hand coding html so that isn’t an issue, but more-so how they will pull it into their email.


See the following link which explains how to import an HTML email directly into Outlook.