opening .wps files

The free LIbreOffice Suite can open the older Microsoft Works (.wps) documents, and print them, but it is not an MS Works editor, so they cannot be resaved with changes to .wps format again. They can be saved to Microsoft Word 2007-365 .docx documents though. LibreOffice 7.6.0 requires macOS Catalina (10.15.*).

If your mother-in-law is using macOS older than Catalina 10.15.7, then an older version of LibreOffice would be needed for compatibility.

I believe one must download a Microsoft specific converter to massage .wps files so that current versions of MS Word can open them.

mblr wrote:

My mother-in-law has a bunch of old .wps files and wants to open, print and edit them with her MacBook Air. Any suggestions?

You can try using Word to open those type of files. OR ask microsoft how you can open those files with a macbook.