<p>I wasn't sure what to put for the return address so I just gave my professors the envelopes with the colleges admissions departments addresses on them. Now I have no clue how to tell if the places I am applying to have received the letters; should I be worried?</p>
<p>First, don’t be worried, the vast majority of mail is delivered with no problems. And since they’re going to a college, they will most likely arrive with no problem.</p>
<p>Second, my advice is to always put your own address for the return. That way, if the letter can’t be delivered for some reason, it will be returned to you, and you will be able to deal with the situation promptly. If it goes to the prof or somewhere else, it may linger or be lost.</p>