You can set the page design for the templates by navigating to Page Design item under the presentation folder as below.

Once you configure above mapping, whenever you create a page from the page template, page design will be automatically applied on the page.

You can find more details here.

https://doc.sitecore.com/xp/en/developers/93/sitecore-experience-commerce/configure-template-to-page-design-mapping.html

Hope this helps!!!

You can set the page design for the templates by navigating to Page Design item under the presentation folder as below.

Once you configure above mapping, whenever you create a page from the page template, page design will be automatically applied on the page.

Moreover you can also set page design using the rules on the Page Design item. Order of precedence of the page design will be as follows.

1. Page design selected on a page level
2. Rules defined for site
3. Page Design to Template Mapping

You can find more details here.

https://doc.sitecore.com/xp/en/developers/93/sitecore-experience-commerce/configure-template-to-page-design-mapping.html

https://doc.sitecore.com/xp/en/developers/sxa/19/sitecore-experience-accelerator/use-a-rule-to-select-a-page-design-for-a-page.html

Hope this helps!!!