Supplementary Materials; Adding Awards and Honors after Submission

I recently received an award for most outstanding young citizen of the year, due to my volunteering efforts. Having already submitted my application, would you suggest adding this as a supplementary material. If so, should I write it in a word document?
Or do you advise against doing so?

Thanks!
This is what Harvard says:
How can I add new accomplishments/awards/accolades to my submitted application?

We understand that you might receive new recognitions or awards after you’ve submitted your application. We welcome the submission of this additional notable information. You may upload information about notable accomplishments and awards using the Applicant Status Portal.