Using Classic Outlook on Windows for personal email, calendar, and contact management
I was having an issue figuring out how the spell check worked. My coworker said when you are in a New Message window, and the Message tab, at the top far right of the ribbon, click the "..." and go down to Editor, and then Editor Settings.
At first, when I tried this, Editor was greyed out, but it might have been because I was already in the middle of composing an email. When I opened a new message I was able to get to the Editor Settings.
All the settings were already enabled, but it seemed I had to open the Editor settings at least once for it to "activate" Now spell check works in my Outlook.
Right-clicking a misspelled word won't work. You have to left-click the word to see the spell-check suggestions.
Edit: