What is an email "alias" or "forwarder" and what is it for? (Linux Hosting)

An email forwarder is an email address that exists only to forward emails to other addresses.  These can be email addresses in your own domain, or to an existing e-mail in a different domain. 

In practice if you create an alias called info associated with one or more people addresses, for example: Paul@yourdomain.com  and Bob@yourdomain.com , all the messages sent to “info@yourdomain.com” will also be received by both Paul and Bob.  But the ”info” address doesn’t exist as an email account you can access, so you cannot configure your e-mail client to log into it, or access it through webmail.