Cosmo Create lets you give your document a title that's different from the name of the HTML file in which your document is stored. Place the cursor in the Title field, then type a title. If the Title field is not visible, choose View > Title.
Notice that when you change the title of your document, an asterisk (*) appears next to the filename in your window title bar. This asterisk appears whenever any change is made to the file. When you save the file, the asterisk disappears.