If your email is configured in POP, a copy of the email messages are downloaded entirely in your device and you access them from your device. The emails can remain remain on the server or can be deleted (immediately or after a defined period) depending of the setting you enter.
It takes more space on your device and more internet usage but you have a hard copy on your computer even if your hosting account terminates.
If your email is configured in IMAP, the email messages are synchronized on your device. Only the Subject of the messages are stored in your device and the content is downloaded when you open the message. You can synchronize the folders and even the sent folders.
It uses less space on your device and reduce your internet usage. It also allows you to access your sent emails from anywhere and to manage your inbox in useful folders. You have to make a download of your emails before your terminate your hosting account or you will loose your messages.
The most common exemple of a webmail is when you access your Hotmail, Yahoo or Gmail from the browser (by login into outlook.com or gmail.com) or from your app in your phone or tablet (going to the Gmail, Yahoo or Outlook icon). Your email are completely stored within the cloud of the email service and you access them using an internet interface.
No configuration is needed, you just need to login with your email address and password but you need to have an internet access to access your email. You also have to make a download of your emails before your terminate your hosting account or you will loose your messages.
Last Update: May 26, 2016