Step 1: Log into your cPanel
Step 2: Once at the main page, click on the Email Accounts icon.
Step 3: In the fields provided, type the name of the account, the password and the disk space you would like to assign to the mailbox.
Step 4: Click the [Create] button to create the mailbox.
You will be taken to a page which asks you for confirmation. Click on Yes to create the mailbox.