How do I enable read receipts for emails?

I’m a total tech illiterate and I seriously need some help here!!!! I was using Outlook Express and got this email asking me to confirm I received it. I accidentally clicked "No"... Is there any way to bring that prompt back up? It’s super important that the sender sees I actually got the message. Asking them to just resend it isn't an option...

Thanks in advance 🙂

As far as I know, once you decline, they probably won't ask you about that email again.
Just send over a new one—maybe just a quick note confirming you got the original message.