Windows "Alt codes" use keyboard shortcuts to insert Unicode characters. These symbols include all of the letters and numbers from various scripts, as well as many other characters. Some of these are astrological or genealogical symbols, and some are even more obscure. The smiley face has no official use in any language or any field, and yet it is the very first symbol to have an Alt code.
Press your keyboard's "Num lock" key.
Press your keyboard's "Alt" key and continue to hold it during the following step.
Press "1" on the keyboard's number pad. The smiley face symbol will appear where your cursor is.