Being a German, the Umlaute (which is the German plural for them) are on my keyboard. I installed other keyboards on my windows system though to be able to switch between my many languages and write those correctly.
To do this you go into your settings
Then "Time and Language",
then "Preferred language"
then "Add preferred language"
and then opens up a new window with tons of other languages.
So when I install a new language, I like to make a "walk over the keyboard" to see where which special letters are hidden. Usually the two keys right of the 0 in the number's line, the two keys right of the P are special letters and also the three keys right of the L are special letters.