You can choose to knock a creature off its feet and leave it prone, as long as no more than one size larger than you and must be within reach. Using an Attack action, make a Dexterity (Acrobatics) check contested by the target's Strength (Athletics) or Dexterity (Acrobatics) check (the target chooses the ability to use). If you win the contest, the target is knocked prone.
Alternatively, a weapon can be used to trip an opponent instead and knock them prone. To do so, simply make an attack roll against the target contested by the target's Strength (Athletics) or Dexterity (Acrobatics) check (the target chooses the ability to use). If you win the contest, you knock the target prone.