Extra Letter of Recommendation

<p>Hi,</p>

<p>I have a question about sending an extra LoR. My research mentor wrote me a letter, signed the envelope (the seal part) and told me to mail it, but he doesn't want his signature out in the open. Will it be okay to mail it in a bigger envelope with my research paper supplement as well?</p>

<p>Thank you in advance!</p>

<p>It’s only an envelope. Of course</p>