try what this webpage tells you. I didn't try it. You may have a try. https://pinyintones.codeplex.com/

Here is a online tool without install, it is a pretty convenient free service. http://www.popupchinese.com/tools/adso

Depending on the application you're using you may either: 1) insert "special characters" from the menu if you're using a word processor such as Open Office Writer or Microsoft Word; or 2) add the Chinese Simplified IME (Input Method) in the language options of your computer, (adding a new keyboard), so that you can type in Chinese and in Pinyin everywhere. Then, just click on the "Open / Close IME Pad" at the right bottom of your screen in the IME Language Bar every time you want to write in pinyin and click on the pinyin tab. It's very convenient because it stays open as long as you need. Here you are!