Reglerna finns på PHB p182:
When you make a high jump. you leap into the air a number of feet equal to 3 + your Strength modifier if you move at least 10 feet on foot immediately before the jump. When you make a standing high jump, you can jump only half that distance. Either way, each foot you clear on the jump costs a foot of movement. In some circumstances. your DM might allow you to make a Strength (Athletics) check to jump higher than you normally can.
Du kan också lägga lite höjd i ditt horisontella hopp med en Athletics check.