Recently I am working on a wordpress project where I want to display short description from clients about us page in footer, then i find this solution to display short description from the page content. Use this code in wordpress get page content by page ID. We can limit the number of words displayed.

Add following code in your functions.php file inside your theme folder.

<?php
if(!function_exists('getPageContent'))
	{
		function getPageContent($pageId,$max_char)
		{
			if(!is_numeric($pageId))
			{
				return;
			}
			global $wpdb;
			$nsquery = 'SELECT DISTINCT * FROM ' . $wpdb->posts .
			' WHERE ' . $wpdb->posts . '.ID=' . $pageId;
			$post_data = $wpdb->get_results($nsquery);
			if(!empty($post_data))
			{
				foreach($post_data as $post)
				{
					$text_out=nl2br($post->post_content);
					$text_out=str_replace(']]>', ']]>', $text_out);
					$text_out = strip_tags($text_out);
					return substr($text_out,0,$max_char);

				}
			}
		}
}
?>

And to display text you have to call the function like

<?php echo getPageContent(11,150); //First parameter is PAGE ID and second is number of words displayed. ?>

OR

You can use the wordpress getPost() function to get content like

$my_postid = 12;//This is page id or post id
$content_post = get_post($my_postid);
$content = $content_post->post_content;
$content = apply_filters('the_content', $content);
$content = str_replace(']]>', ']]>', $content);
echo $content;