How to add custom HTML to node content?
Create a custom template file node--type.tpl.php where type is the machine name of your content type. 

Place it in your theme's templates folder /sites/all/themes/YOURTHEME/templates and clear/flush the cache to see changes.

Ex: Article content type: node--article.tpl.php

&lt;?php print render($content['field_xxx']); ?&gt;

// custom html goes here

&lt;?php print render($content['field_yyy']); ?&gt;