Wondering if we could make labels with our name, address, etc. and for the postage paid, etc? Also, how would the postal clerk know we want a return receipt if we drop the letter in the outgoing drop box?
Yes you can simply print your own labels...
If you need a return receipt you can get the green card supplies from any post office, fill one out and put it on your envelope. It will then be returned to you signed.
However in some cases the post office would take your mail at the counter and give you a receipt with $0 on it... This is a hit or miss though... One time I went to the counter and the post clerk said that he cannot scan my mail and put it in the outgoing basket without scanning them... then at some point down the line it got scanned and I was able to track the mail.
I have used this process and it hasn't worked. They sent everything back to me and sent a letter stating that this was for international only. These folks are so dumb and stupid but its not their fault. I sent a packet for them to study, but I'm not sure it will do any good. All I know that 11.00-12.00 for each letter sent is very costly and if anyone knows how to help, please let me know.
The reason your mail is not being accepted is because the International Mail Manual (IMM)742 Stamps Not Affixed; 742.1 "Marking" & 742.2 "Parcels without Postage Stamps" comes from the "IMM Content" blue colored column on the left-hand side of the web page #7 "Treatment of Incoming Mail". So, in a nutshell the Postal Agent was correct in the statement made. https://pe.usps.com/IMM_Archive/HTML/IMM_Archive_20150531/immc7_011.htm