From WordPress 4.7, you can now assign Custom Page Templates to other post types along with the ‘page’.
To achieve this in addition to the Template Name header, the post types supported by a template can be specified using Template Post Type, as following:
Template Name: Full-width page layout
Template Post Type: post, page, product
Adding the above to your theme files can be done by replacing the files in a child theme so your Child theme files will overwrite the ones from the Theme source. You will also need to make sure you activate ‘Page Attributes’ under Advanced Options, Supports in your particular Pod.