The tilde symbol looks like a sideways letter "S" when displayed in text. If you frequently type in Spanish, you're probably familiar with it; the tilde is used much more frequently in Spanish than in English. All computers come equipped with a "Tilde" key that will type a tilde when pressed in conjunction with the "Shift" key. If you want to display a tilde over a letter, you can also add a special character or symbol with the appropriate letter and a tilde by using the options in your word processor.
Open your word-processing software of choice.
Press and hold the "Shift" key.
Press the "~" key while holding down "Shift" to type a tilde into your document.
Click your word processor's Tools or Insert menu. All word processors allow you to insert special characters into your document. Click the menu option for symbols or special characters. Here, you can find letters with tildes over them and add them into your document.