It's wysiwyg editor content. So, you need to use \Magento\Cms\Model\Template\FilterProvider
class to filter cms page content and display.
Follow this below code :
Using construct method
protected $_filterProvider;
public function __construct(
.....
\Magento\Cms\Model\Template\FilterProvider $filterProvider
.....
) {
.....
$this->_filterProvider = $filterProvider;
.....
}
public function getContent($identifier)
{
return $this->_filterProvider->getPageFilter()->filter($this->getPage($identifier)->getContent());
}
Using Object Manager
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$content = $objectManager->create('\Magento\Cms\Model\Page');
$myCmsData = $content->load('my_page_identifier', 'identifier');
$cmsContent = $objectManager->get('\Magento\Cms\Model\Template\FilterProvider')->getPageFilter()->filter($myCmsData->getContent());
echo $cmsContent;