Swedish letter typing with English Keyboard for Mac

To get the umlaut above a letter:

1. Hold down the Option key, and type a u (the letter u).

2. Let go of the keys (don't hold them down for step 3).

3. Type the vowel over which you want the umlaut to appear.

Hold the Shift key down in step 3 Above.

Option+A = å

Shift+Option+A = Å

Option + u, then a = ä

Option + u, then shift + A = Ä

Option + u, then o = ö 

Option + u, then shift + O = Ö 

Reference at https://familysearch.org/learn/wiki/en/Sweden_Typing_the_letters_%C3%85,_%C3%84,_and_%C3%96