How to fill up my thighs?

To fill up your thighs, focus on strength training exercises that target the quadriceps, hamstrings, and glutes, such as squats, lunges, and leg presses. Incorporate progressive overload by gradually increasing weights or resistance to promote muscle growth. Additionally, ensure you're consuming enough protein and calories to support muscle development. Consistency in your workout routine and a balanced diet are key to achieving your goals.