is the bishop better or the knight

'The weaker the player the more terrible the Knight is to him, but as a player increases in strength the value of the Bishop becomes more evident to him, and of course there is, or should be, a corresponding decrease in his estimation of the value of the Knight as compared to the bishop.' - Capablanca

Do not exchange your bishop for a knight without your opponent attacking your bishop with a pawn. Few examples

Here B x c6 is not good as the bishop is not attacked by a pawn.

Here B x c6 is good as black made a pawn move

The general consensus is that an unpaired bishop is more or less equivalent to a knight. But that the bishop is better in more positions than when a knight is better.

it often depends on wether your bishop is a good bishop or a bad bishop. a good bishop is one where the majority of your pawns are on the opposite color to it and a bad bishop where your pawns are on the same color square.it also depends on whether the position is opened or closed as bishops thrive on open positions and knights on closed. ignore my spelling