It’s not easy to make a jump feature and it depends on your game your wishes and your abilities.
The way I do that in my game is that I move the character up for a short while and then I move the character down, until the character reaches the ground. But I also check how far the player wants to jump and apply that in the jump by moving the character forward at the same time.
But how you do this is completely dependent on the rest of the game.