The files defining each Page Template are found in your Themes directory. To create a new Custom Page Template for a Page you must create a file. Let’s call our first Page Template for our Page snarfer.php. At the top of the snarfer.php file, put the following:
< ?php /* Template Name: Snarfer */ ?>
The above code defines this snarfer.php file as the “Snarfer” Template. Naturally, “Snarfer” may be replaced with most any text to change the name of the Page Template. This Template Name will appear in the Theme Editor as the link to edit this file.
What follows the above five lines of code is up to you. The rest of the code you write will control how Pages that use the Snarfer Page Template will display. See Template Tags for a description of the various WordPress Template functions you can use for this purpose. You may find it more convenient to copy some other Template (perhaps page.php or index.php) to snarfer.php and then add the above five lines of code to the beginning of the file.
That way, you will only have to alter the HTML and PHP code, instead of creating it all from scratch. Examples are shown below. Once you have created the Page Template and placed it in your Theme’s directory, it will be available as a choice when you create or edit a Page. (Note: when creating or editing a Page, the Page Template option does not appear unless there is at least one template defined in the above manner.)