this is not easy. check out this game from a Grandmaster versus a computer from 1978 ( much weaker than today's computers ) where this ending occured. It was a Draw as Browne could not win within 50 moves !
https://www.chessgames.com/perl/chessgame?gid=1480950
here is a more modern example between Grandmasters where a Draw was also the result !
http://web.chessdailynews.com/can-a-2750-win-a-queen-vs-rook-endgame/
https://syzygy-tables.info/?fen=3k1r2/8/8/8/8/8/4Q3/4K3_w_-_-_0_1
There are Tablebase.
Learn yourself.
Chess is solved up to 7 men TB.
Some positions, are draw due to 50 moves rule. Some position are win within 50 moves rule.
White win in 45 moves.
White win in 55 moves.
White win in 62 moves. One of the longest win or the hardest position to win with KQvKR.
Pls help , this is so confusing