Favored Enemy is a Ranger feature gained at level 1 in the 2024 SRD. You always have the Hunter's Mark spell prepared.
You always have the Hunter's Mark spell prepared. You can cast it twice without expending a spell slot, and you regain all expended uses of this ability when you finish a Long Rest.
The number of times you can cast the spell without a spell slot increases when you reach certain Ranger levels, as shown in the Favored Enemy column of the Ranger Features table.