In Shopify, navigate to your products and filter for the items for which you want to change the template. Then, select them and click on bulk edit. Under the columns drop-down, there is an option for “Template.” There, you can choose the template of your choice. Keep in mind that you can only select published templates. If the template is removed, the product will revert to the default template.
You can also do this with a bulk editor app.
