How to type Umlaut letters (ä, ü, ï, ö, ë, ÿ) on Keyboard
Place your cursor at the desired location within the document. Turn on you Num Lock. Press and hold the Alt key on your keyboard. Whilst still holding on to the Alt key, press the umlaut alt code and release the alt key. For example, to type umlaut o, press and hold the key and press 0250 on the numeric keypad.