I know web hosting. But can i know what is email hosting, and why do people need email hosting??

Some companies may choose email hosting to host their e-mails elsewhere, in case their web server goes down.

Some companies may only need to host their email somewhere, where they are working without a website. Generally these are companies who work in a different models, their customers could be regulars and hence there is no need for a website. Web hosting may be cheap, but to get someone to design a website is a different story.

Most email hosted on the same web servers does not have any backup MX. That’s mean if the single server fails, all the emails will be bounced back to the sender’s server to be queue for delivery again.

For companies who specialize in email hosting, they will have a few servers to handle incoming/outgoing emails to ensure that the uptime of the email servers are close to 100%.