You can use the Keyboard Viewer to add accent marks to characters. The Keyboard Viewer shows the characters for the keyboard layout or input method selected in the Input menu. For example, if U.S. is chosen in the Input menu, you see the characters that appear on a U.S. keyboard in the Keyboard Viewer.
Choose Show Keyboard Viewer from the Input menu on the right side of the menu bar.
The Input menu appears on the right side of your menu bar and looks like a flag or character. If you don't see the Input menu, go to Viewing Keyboard Layouts for Other Languages for instructions on viewing the Input menu.
Press Shift, Option, or Option-Shift to highlight the available accent marks in the Keyboard Viewer.
The accent mark keys are highlighted. Depending on your keyboard, you may not need to press any of the modifier keys to see the accent keys.
Place the insertion point in your document where you want to type.
Press the modifier key you pressed in step 2 (Shift, Option, Option-Shift, or none) and then press the key on your keyboard that is in the same place as the accent you see in the Keyboard Viewer.
Release the modifier key, and then press the key for the character you want to accent.
For example, on a U.S. keyboard, to make é appear, press Option and E (the accent key), and then press E (the letter on which you want that accent to appear).