Hi.
It is a stalemete (draw), when a player does not have any legal moves but is not checkmated.
We all had this problem as beginners: having a big material advantage and the game won, and then stalemating the opponent and drawing the game. With some practice you can learn to avoid it.
Greetings.
Probably, in the beginning of chess time everyone would either play until the king was actually captured or the game was decided a draw after both sides agreed that would never happen. In those days there was no stalemate. But then someone invented "checkmate" to politely end the game without the barbaric slaughter of a Royal. After that the same thing happened as with kings who lost a real war but physically survived it. It opened the door to varying follow-ups. Possibly the king was still axed but he might also be jailed forever or banned from his land. A similar thing happened to chess after the king capture was banned. Depending on the circumstances the king either loses everything (checkmate) or gets the generous half point (stalemate). That's what happens when humans get civilized!
Why, when I have the computer beaten, is it called a stalemate? I have the king cornered and they cannot move.