You can upload an Excel spreadsheet as a specific content type. When adding a new article you can select the 'Image/PDF/Excel' tab and then drag and drop (or click to use the file picker) to upload an excel spreadsheet.

NOTE: You will need to make sure the spreadsheet is a .xslx file (not a .xlsxm)

Once it has loaded click 'Post Upload'.

You can view a preview of it by then clicking on the new article.

If you are looking at the preview of the article (after clicking on it from the Article menu) you will see the 'Edit' button in the bottom right. Click this and then use the file picker/drag and drop to select the new spreadsheet