The Personal Stationery file that ships with ClarisWorks 3.0 provides instructions in the body of the document about how to modify it to meet your needs. One of the instructions recommends using Control-Click to modify the text in the Footer this will work for Windows users, however, the key you should use with the mouse click is Command if you are using a Macintosh.
The Personal Stationery file is available from the New Document dialog under the Home Stationery category.