Sometimes it is not possible or permitted (due to licenses) to embed a font. Only then consider converting the fonts to outlines. You can read below how to convert fonts to outlines in Illustrator:
Go to 'Type' and click on 'Create outlines'.
Your text has now been converted to outlines.
 Save your file according to these steps. Note that you can no longer change text with the text editing tool. Save your file under a different file name, so that your original file is still saved seperately.