1) Login to your cPanel Account, follow this article on how to do that click here
2) Under the Domains section click on the 'Aliases' button
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3) Fill in the Domain field with the domain you want to add to the current domain, then click the 'Add Domain' button
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4) A message will appear, click on the 'Go Back' button
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5) That is it, easy peazy, your added domain will now show the same content as your current domain attached to your cPanel account
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