In order to edit the “Powered by OpenCart” text at the bottom of your OpenCart store, you need to edit the file “/catalog/language/english/common/footer.php”.
$_['text_powered'] = 'Powered By <a href="http://www.opencart.com">OpenCart</a><br /> %s © %s';
Simply replace the text with whatever you’d like. As can be seen, HTML is accepted.
