How to type German umlauted vowels, long ‘s’ and ess-tsett using your Windows keyboard: 
 
1. Make sure that the NUM LOCK on the number keypad is ON.
2. While holding down either ALT key, type the following on the keypad: 

ä   0228  ö   0246  ü   0252 
Ä   0196  Ö   0214  Ü   0220 
ß   0223  ſ   0383 

 
All of the above German letters are available to ‘paste’ into your document, by using the character map available in Windows. In Word, for instance, you would open the Insert menu, click on Symbol, and then More Symbols to find the character map. (Windows does save the last 20 pasted characters you have used, so you will not have to go searching the character map each successive time you need to use a special German character.)