Steps to create new template for WordPress page. This will help you to customize your template for single page.
1) Create new php file, For example: payment-page-template.php in wp-content/themes/{your_active_theme}/
2) In payment-page-template.php, paste the below sample comment code in this newly created file.
<?php
/*
Template Name: PaymentPage
*/
3) Once this template is created you can select this newly created template in wordpress page.
Sample screen shot:
