Here is how to disable Office File Viewer in Microsoft Edge. This will make Edge to download Word (docx) or Excel (xlsx) files instead of opening them.
By default, Microsoft Edge opens an Office file, e.g. a Word (docx) or Excel (xlsx) document, when you click on a link to it on some page in the browser. Many users consider this a convenient feature, as it doesn't require Microsoft Office or LibreOffice to be installed for opening such file. On the other hand, some users may prefer to use a locally installed app, that also allows editing and perform extra operations on the document.
