Volunteer Service

I have a small question, maybe some can answer it. I submitted my common application; however, I forgot to list most of my community service in there. I actually received various letters thanking me from the service I did. I wanted to know if its too late to add this to my application, I have heard some say that I can submit it as supplementary material;however, I am unsure if it is true. Should I go ahead an submit something that shows my community service to my college?