Fa cup derby county vs manchester united today at 845pm
I'm afraid that's not correct. The FA Cup is a real competition, but the match you're referring to is not taking place today at 8:45pm.
Derby County and Manchester United are both English football clubs, but they are not scheduled to play each other in the FA Cup today. The FA Cup is a knockout competition, and the matches are typically played on weekends, with the exact dates and times announced in advance.
If you're looking for information on upcoming FA Cup matches, I'd be happy to help you with that. Alternatively, you can check the official FA Cup website or the websites of the two clubs you're interested in to see their schedules and fixtures.