What address are we supposed to send any additional recommendation letters to be added to our profile? These aren't the teacher online ones, they're the ones that must be sent by snail mail.
They should follow the conventions of any LOR for the purpose of any college admission. The people you ask should be familar with the format. I suggest that you include a brief resume listing your extracurriculars, job history, awards, etc. to assist them in their writing. Best wishes.