Shipping Templates are designed to simplify shipping settings setup with multiple custom configurations, flexible transit times, granular delivery regions, and reports. Optimize your shipping settings and increase sales with easy-to-use templates all within Seller Center or using your preferred integration method. If you want to create your custom shipping template then you can create a new one from the Shipping Template section as specified in the screenshots:

Choose the shipping template in Global Settings –> Product –> Product Export Settings –> Shipping Specific –> Shipping template as specified in the screenshot:

You can fetch shipping templates that you created on Walmart by using the Get Update Shipping Template button as specified in the screenshot: