Question

what steps do we follow to change paper size

Answer 1

If your printer does this, and you want to change the paper size used for your document, you should follow these steps:
Choose the Page Setup option from the File menu. ...
Select the Paper Size (Word 97 or Word 2000) or Paper (Word 2002 or Word 2003) tab. ...
Select the appropriate paper size for your document.
Click on OK.

I hope it help you