Rules Question Concerning Checkmate and the Clock

If you move and it's a checkmate, do you HAVE to hit your clock for it to count? Or by having a checkmate, that ends
the game automatically? Thinking that your clock ran out after you moved checkmate, and your were slow to hit your
clock. All this is OTB...USCF and Fide.

Checkmate ends the game immediately. So does stalemate.

Can someone explain me what is USCF and Fide (I understand it is some sort of rating I think, but isn't Fide and USCF all OTB)

also yeah as tpr said it ends the game immediately also if you resign ( I was once in a blitz tournament, with my friend, my game ended so I watched his and the final move was stalemate, they both were like 1sec on the clock and after a7, which was the stalemate my friend resigned (and his opponet hit the clock) but then there was a disccusion and we went on asking the judge and it was a draw, even though my friend resigned after the move)

USCF is an abbreviation of the United States Chess Federation, which is obviously the US Chess Federation, and FIDE is short for Féderation Internationale Des Échecs, which means The International Chess Federation in french. (I think its french lol)

with that I can say CHCF (china federation) I assume then, also RUCF ?

no, you do not HAVE TO hit your clock, if you have check mated your hapless opponent.

but you SHOULD hit your clock, to prevent any disputes --- such as your flag may subsequently fall, and there turns out to be a dispute about the mate. this is actually covered in the uscf rules - 13a1, edition 6. i think there's no way you should mate someone and not hit your clock.

Checkmate counts of course. But if there is no arbiter, they play on and someone resigns first this can count. I mean imagine they figure out that at home!?

Imagine, there is stalemate, one opponent resigns and signs his scoresheet? What to do? In such case the resignation is valid.

i had this experience once in a blitz tournament, I checkmated my opponent and then my flag fell