You can send together and mention it on cover letter.

@Charlie SC ok. Thank you.

yes, send all envelops in one package.

@Charlie SC My RFE specifies that a copy of the RFE must be sent to speed up the process along with the medical exams. They do not ask for a cover letter. Which letter are you referring to?

I am saying to prepare a letter that mentions what you are adding as a response.

I have not sent any cover letter, I only sent a copy of my RFE along with the sealed envelope containing the medical exams (I sent mine and my dependents), I put everything in an envelope and asked for a signature when it was delivered. USPS, I already have the notification in the application that my response to the RFE has been received.

and I already have a response from USCIS that my response to the RFE has been received.

Hello, thank you all for your contributions. I discussed it with my lawyer and he told me that in my case it can be sent together because we are married.