Difference between web based mail and a client based mail
Both webmail and an e-mail client perform the same function: they allow the user to send and receive e-mail. However, an e-mail client requires the user to install software directly onto their computer, if the software is not installed, e-mail may not be accessed. Also, many e-mail clients cost money, but are generally more secure.
Webmail, on the other hand, is a free service, hosted in the cloud. The cloud service will automatically synchronize your e-mail to all your devices, including your desktop computer, tablet, or smartphone.
Webmail
With webmail, you read and send email through your web browser and a web-based interface. In fact, webmail allows you to access your email from any web browser, on any device, as long as you are connected to the Internet.
Examples : Gmail, Hotmail, Yahoo mail, AOL mail
Email client
An email client is a piece of software that is installed on your computer. You then use this software to download your emails from the server to your computer and from there you can read an send emails.
In other words, in order to use an email client to access your domain emails, you will first need to install the email client software on your computer.