Dear SK,
Good day! Thank you for posting your query in our community.
Based on your description, you want to print the Word document from A3 to A4 format.
Generally, you will lose the format of the data if you try printing A3 size document to A4 size because of the size.
A workaround is that you can first save the Word document as a PDF file, and then open the PDF from browser, select the Print icon> More settings > change the Paper size to A4.
Sincerely,
Jazlyn | Microsoft Community Moderator