Hi LoganSaj,
You can do this using a Heading Style, prefixing the Heading's numbering scheme with 'Chapter '. See:
http://support.microsoft.com/kb/290953
and
http://www.shaunakelly.com/word/numbering/OutlineNumbering.html
You might also want to take a look at: http://www.shaunakelly.com/word/numbering/UseBuiltInHeadingStyles.html