Foreign words with marks over letters (like umlaut in German over O)

Thank you to those who helped me alter the speed of playing the music.
I am the one who transcribes music for learning in a choir. Many of the pieces we do (a Chamber Choir) are not available from learning forums.
When I first downloaded MuseScore, I bought the book for guidance. However, since then there have been many changes. Some I find, some I don't know how to get. I need to write the words on the music score and it would be helpful if I could access where I look to add Umlauts in German (spelling unknown) and other things if in a foreign (ie Not English) format. The first version of MuseScore was easy but now I can't locate it. I have a replaced laptop since then and ALT does not work on MuseScore. I also have the Character map but that won't link either.
I would be very grateful if someone could assist me. If you do, I am thanking you in advance!