Hey Darryl!
Welcome to the community! 
At this moment, Webflow does not provide any sort of email hosting as a part of their packages. After a quick search of the Features Wishlist, I couldn’t really find anything to suggest that this would be something that is added in the future either. Webflow is more focused on developing a world-renowned No-Code product more than anything.
Personally, I would suggest you take a look at either Office 365 or Google Workspace (formerly Google Suites, Google Apps). These are both great tools that I have used myself to get branded email addresses.
If you’re wanting to simplify their billing so that they only pay one bill for their hosting, you could also just add in the cost of the Email Hosting to their Webflow bill by using Client Billing. You can find more information on how to do that here.
Hope my suggestions help you out! If you have any further questions, or need clarification on something I said, I would be happy to help more!