Go to any dictionary-type website and type in the word you're trying to spell. Doesn't matter if it's butchered. The site should select some differing alternate spellings and words and the one you want, with the needed correct accent, should be displayed. Then use your mouse to cut just the letter and paste it into your document.
I have used this method without fail for years; never used a desktop app or widget to select an accented letter. Try www.dictionary.com. The character site already listed is a rich source as well.