According to the Monster Manual, in the Player Characters as Lycanthropes box on page 207:
A character who becomes a lycanthrope retains his or
her statistics except as specified by lycanthrope type. The character gains the lycanthrope's speeds in nonhumanoid form, damage immunities, traits, and actions that don't involve equipment. The character is proficient with the lycanthrope's natural attacks, such as its bite or claws, which deal damage as shown in the lycanthrope's statistics. The character can't speak while in animal form.
Inherited Abilities
The player character does inherit the following from the Werewolf stat block:
Damage Immunities
Traits
- Shapechanger
- Keen Hearing and Smell
Actions
- Bite (Wolf or Hybrid form only)
- Claws (Wolf or Hybrid form only)
It is unclear whether the following are inherited:
Embrace vs. Resist
It is unclear whether the player character's inheritance of those abilities is predicated upon embracing the curse.
The Monster Manual says:
Some individuals see little point in fighting the curse and accept what they are. With time and experience, they learn to master their shapechanging ability and can assume beast form or hybrid form at will.
Which does seem to imply that the ability to shapechange at will is limited to characters that embrace the curse. Though that limitation is not made clear in the section on those that resist the curse. Confusing the matter even further, it also seems to imply some sort of time/training-based requirement for the ability to be used, but nowhere is this clarified or elaborated on.