Applicants are not be able to upload letters of reference themselves.
However, letters of reference that are sent directly from the applicant to CaRMS may still be processed, specifically when an applicant has immigrated to Canada with the letters in their possession and no longer has the opportunity to have a letter submitted directly by the referee. If you feel this situation may apply to you, you must send a notarized or certified copy of the letter by mail/courier. In addition, you must create a reference request for it in your CaRMS account's "My Documents-->Letters of Reference" section as this will generate a coversheet.
You can then mail the letters to us with their request coversheets (they can all be sent in the same envelope as long as each have their corresponding coversheet included).
Original letters of reference submitted to CaRMS will not be returned to applicants.