Working on inner thighs is a very targeted area! The squeezing motion of the legs best isolates the inner thighs. Overall, exercises like squats, lunges, leg raises etc are good exercises and there are plenty of lower body bodyweight workouts that will workout your lower body as a whole.

Strengthening the inner thighs will increase the size of them (along with any muscle) so if your daughter's goal is to lean them out (bigger thigh gap is a very popular goal), lowering the overall body fat percentage is a better way to achieve that. Sarah Kusch and Pace and Go are two experts that are pros at blending strength with cardio.

Here are 4 balanced series that come into mind.

Bodyweight Bootcamp
Bodyweight Bootcamp
HIIT Afterburn
HIIT Afterburn
x5 Intensity
x5 Intensity Workouts
Tight in 28
Get Tight in 28 with Sarah Kusch

These workouts are actually programmed in a way that distributes the load throughout the body which is better for getting your body adapting without lots of soreness/less recovery if you just did all inner thigh exercises. Even core videos in there series sprinkle in leg exercises while keeping your body balanced in the grand scheme of fitness progress.

Also, this series has lower body emphasis:

Ellysia Noble's Lower Body Series
Lower Body #1 - Step Ups, Hip Raises, & Sumo Squats

Hope this helps!