The typeface used throughout the LMS is set and cannot not be changed. It is designed for readability and accessibility and speed. It has been selected for ease of use with different screen reading and viewing software in mind as well as aesthetics that match the rest of the site. Although you do have an HTML editor at hand, we recommend sticking to theme colors and typefaces.
Where there is freedom is in the SCORM Package activity. That package is self-contained and is launched from the LMS so there is a possibility of using a different font. The design of the SCORM package will be mostly controlled by the designer or the developer building the SCORM package. If you have any input, you should communicate that in the storyboard or outline.