An alias is the first part that forms a mail that is before the @, for example the one in [email protected] the alias is david.
The alias of mail is a service that allows to assign to the same email several aliases, when someone sends an email to any of the alias previously configured by the client this will be received by the main alias.
This means the following, you can create the mail [email protected] which is your main email (alias david), sometimes it is necessary to have active several accounts that are controlled by you as they can be [email protected] (commercial alias ), [email protected] (alias info), to have the control of them you can either create them independently and configure them to turn independently in your Outlook, which is inefficient, redirect them all to the main email which is expensive, or the easiest way to assign the main account the alias info and commercial. This way when someone sends an email to [email protected] will be received in his account of [email protected]
This service is unlimited and you can configure it online through the plesk control panel.