Before we dive into the details, it’s important to differentiate between a hosted email provider, webmail, and an email client, as these three are often looked at as one. As an example, let’s take Bluehost as an email hosting provider, discontinued Outlook Express as an email client, and Gmail as webmail.
Any given business can purchase a plan from Bluehost to store, receive and send emails from their servers. The very same business will need a tool to write, read and access those emails, that tool is called MUA (Mail User Agent). This can be done either via an email client (Outlook Express) or webmail (Gmail).
Using webmail, one would send, receive and read emails via a web-based application that is connected to a cloud email hosting solution and does not download the actual files to local computer storage. An email client, on the other hand, is a desktop application that downloads emails from the server to a computer and reads them from local storage.