E-mail aliases can be used as temporary disposable addresses that can be published on the Internet. When spam starts coming to an address that was set up as an e-mail alias, you can remove that alias and create another one.
Go to "Mail", and click an e-mail address.
Select the "E-mail Aliases" tab.
Type the alias name.
To create a second alias, click the "Add e-mail alias" link. Type in the name and click "OK" when done.
That's it! Now you know how to create e-mail aliases in Plesk.