Hi Mandar Khadilkar,
Welcome to the fantastic world of wikipedia.
You had asked to Harshal....
How I can type in Marathi Language?
Can I use any of the Devnagari Font or DO I have to use any specific font only?
The answer is that goto the page...
http://saraswaticlasses.com/download/translate.html
(Refresh the page if not fully loaded.)
Type in english something like this...
aapaN kase aahaat?
and click on translate. The text you typed will be translated into Unicode that you can copy and paste here at wikipedia or any other blog site.
I hope this helps.