When creating pages it's common to use commercial trademarks, copyright, umlaut, and other non-keyboard symbols. therefore it's important that you have the means to input these special characters.
Find the "Character Map" utility in your computer's System Tools folder. Click the symbol you're interested in, and note the keystroke information at the bottom of the box. You execute these by holding "Alt" while keying the numbers on the numerical keypad of your keyboard (not the numbers across the top of the board).
Use Word or another desktop application to create your text with the special characters that you want. Copy and paste the text to the wiki page you're editing or creating.