An asterisk is meant to denote that there is more information about the information next to the asterisk. For example, you might be writing a document that includes referential information that does not fit well with the text you are writing. Inserting an asterisk next to this text allows the reader to know that they may look at the end of a chapter or the bottom of a page to find where you have inserted more information.
Open the document on which you want to include an asterisk.
Press and hold the "Shift" key.
Press and release the "8" key. The asterisk will appear on the screen.