If you want to change the paper size in Microsoft Word, here is how you can do that. It is possible to change the default paper size of 8.5×11 inches to anything else as per your requirements.

At 8.3 x 11.7" (210x297mm), A4 paper is slightly narrower and a little longer than "A" size 8.5 x 11" paper (216x279mm). The A4 is part of the ISO "A Series," where A0, the first dimension ...