College application essays do not need titles. In fact, most application essays do not have one. You may, of course, choose to add one if you feel like it adds value to the essay, but in most cases I would suggest not using one if not explicitly asked to provide a title.
The "Why Us" supplemental essay is your chance to show why you applied to a particular school and what you'll bring to it. These tips have helped members of our team get accepted into their dream schools! For more detailed tips, check out "Why This College Essay Guide + Examples" by the College Essay Guy.