If you used a filter such as '@yahoo.com' all email from any user whatsoever using that domain would end up in the junk folder. A specific email would have an effect like that of a kill-filter but usually junk or spam varies the ID source so it wouldn't block it for long.

Hi, thanks for replying. Are you able to send me a link where it would show how to set up that type of filter? I looked at a couple items but was more confused than anything else. Any help would be greatly appreciated. Thanks!!!!

Hamburger (top right)/Tools/Message Filters

Thanks, that is where I have been looking just not sure how to do a server like @yahoo.com or the one I am dealing with a lot right is @live.com. I want to block anything and everything from @live.com. Do I just put in the Filter Name @live.com or do I use something like *@live.com.?

Also how do I fill out the rest of the screen. I tried adding @live.com and so far no luck with blocking sending it to junk mail.

https://support.mozilla.org/en-US/kb/organize-your-messages-using-filters

ok, thank you, I will look it over again

Also how do I fill out the rest of the screen. I tried adding @live.com and so far no luck with blocking sending it to junk mail.

Now I am starting to comprehend you are trying to change a junk mail issue so everything up to now it basically null and void. Your are not trying to block anything, you are trying to not have someones mail appearing in the junk or spam or Bulk folder! Is that the case? (what is the mail provider, what is the folder name and most importantly of all when you view the email in the list, does it have a red flame icon showing or it is a grey sort of colour?