convert older textedit doc to a current format

If they are Rich Text Format (RTF), Rich Text Format Directory (RTFD), or plain text, they should open in the current TextEdit, Pages, and Bean. If they are not RTFD, they should also open in LibreOffice Writer or MS Word.

Click once on one of these 1996 documents and then press option+cmd+i to open a Finder information panel. What is shown for its kind and its extension in name & extension?

If they are .doc, which is the ancient Microsoft document format, then you will likely need LibreOffice to open and resave as RTF for compatibility with the current TextEdit.

A file with a .app extension is an application, not a document type that TextEdit can open, despite what it shows with the Open with application being TextEdit.app.

For kind, you should see one of these choices that TextEdit can open:

• Rich Text Document (RTF)
• Rich Text Document with Attachments (RTFD)
• Microsoft Word 97 - 2004 document (DOC)
• Open Office XML Word processing document (DOCX)
• Open Document Text (ODT)
• Plain Text Document (TXT)
• WordML (XML)