I am new to zencart and want to create custom page for categories, can anyone help me for that to create custom categories page?
If you want to create a new page in Zen Cart, you have a couple of options:
Use EZ Pages - go to Admin->Tools->EZ Pages and add your page.
Start with a new page template such as the About Us page, which is available in the Plugins area for Zen Cart here: http://www.zen-cart.com/downloads.php?do=file&id=86