You may sometimes want to share your documents with people who use earlier versions of Word.
Word 2007, 2010, and 2013 can open .docx files created with Word 2016.
If you aren't sure which earlier version they're using, you can save documents in the Word 97 – 2003 (.doc) file format.
Create a new document in Word 97 – 2003 format
To create a new document in Word 2016 and save it in Word 97-2003 format
Go to File > New.
Select Blank document to create the new document.
Go to File > Save As.
Choose a location to save the file.
Type a name for the document.
Select Word 97-2003 Document (*.doc) from the list. This changes the file format from .docx to .doc.
Consequences of converting .docx to .doc format?
When you save a document created in Word 2016 (.docx) in Word 97 – 2003 (.doc) format, some features and elements may be lost or behave differently.