Report to whom? With an expectation of what happening exactly? See https://support.mozilla.org/en-US/kb/blocking-sender

What Matt said. What do you mean "report"? Report to whom? Unwanted mail cannot be dealt with the same way as unwanted phone calls (if that's what you mean). Some mail service providers like Gmail may let you report spam to help them identify spam at the server for that particular service, but that has no effect on the same message being received through some other mail service provider –– and again it's not even clear whether that's what you mean by "report". What generic mail clients like Thunderbird do is provide their own local junk filtering capabilities on top of the filtering done at the server, which you may then train by marking as junk messages they didn't initially recognise as such. And you may also set up filters to tell Thunderbird to do bad things to incoming messages that meet some criteria if you wish, so you never get to see them, but be careful with that or you may end up inadvertently missing messages you want to keep if you do it wrong. You may learn about those Thunderbird features and capabilities here: https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages