A family of Microsoft word processing software products for creating web, email, and print documents.
Your screen shot indicates that at least one, possibly all, predefined building blocks (page number formats) have been replaced with other ones.
Are you running Word for Windows? In that case, do the following: Exit Word and then delete the Built-in Building Blocks.dotx template to restore the standard set of formats. To find the template in a US English installation, go to %Appdata%\Microsoft\Document Building Blocks\1033\16. You can enter this path in the Run dialog box (Windows logo key + R) and press Enter.