Discuss rirri's answer to: How do i mark an e-mail return receipt

AOL webmail no longer offers the Return Receipt option.  Newer versions of the AOL client don't, either, but older ones still do.  In AOL, the Return Receipt option is a checkbox at the bottom of the Write Mail window.  Some third-party clients (like Thunderbird) also have the option - check the help menu for details.

Be aware that some e-mail programs give the recipient the option of not responding to Return Receipts so not getting one does not mean your message was not received.