Microsoft Word's grid template designs are anchored within the header and footer, so I need to double-click the header at the top of the page to activate those background designs.

How to create Word template in Office 2019 The option to create a template is available on Word included with Microsoft 365, Word 2019, Word 2016, and older versions.

Susan Harkins shows you how to use Microsoft Word's gridlines settings to position text and objects in your documents.