Question about sending additional attachments

Because I attended 3 different undergraduate institutions, I want to send an additional attachment explaining my educational background more in depth to schools I already applied to. What would be the best way to send this to admissions committees?

Just send an email to the general admissions office email address. something like:

"dear addmissions officer,

I would like to add and addendum to my recently submitted application. Attached is the relevant file.

Thank you for your time,

ME"


should get a response in a day or two saying that it has been attached.

Ok thanks that sounds good. LSAC said that I should physically mail it, but I think that would take a little too long.