My passport is going to expire next month.?
It depends on your country. But basically however you got your passport in the first place should work for renewal. Check the Internet, most governments have a government office webpage that tells you the exact process. In my country - Australia - we can go to a Post Office to get a form to do it. If you're living overseas, ie in a different country from your nationality, you can contact the embassy in the country where you live. It usually takes a bit of time, do if you're planning a trip soon and your passport will expire soon (within six months of the planned end of your trip) you should do it soon, as it will leave you without a valid passport for a few days or weeks.