Select the letter you want to accent
Go to the Insert tab
Click Symbol
Choose More Symbols
Select the accented letter from the list
Click Insert
Close the Symbol window
Use keyboard shortcuts for common accents
On Windows, use Ctrl + ‘ then the letter for an acute accent
On Windows, use Ctrl + ` then the letter for a grave accent
On Windows, use Ctrl + Shift + ^ then the letter for a circumflex accent
On Windows, use Ctrl + Shift + : then the letter for an umlaut or diaeresis
On Windows, use Ctrl + Shift + ~ then the letter for a tilde
On Mac, press Option + e then the letter for an acute accent
On Mac, press Option + ` then the letter for a grave accent
On Mac, press Option + i then the letter for a circumflex accent
On Mac, press Option + u then the letter for an umlaut or diaeresis
On Mac, press Option + n then the letter for a tilde