I wonder what causes frecklesㅠㅠ

Hello!! I have more and more concerns about my faceㅜㅠ I keep leaving inquiriesㅜㅜsob sob I'm sorry I have so many freckles on my face What is the cause of freckles?ㅠㅠ I'm leaving a post this time because I'm curious about the cause of freckles!!! I'm curious because I think I need to know the cause of freckles to solve it fundamentally. I want to figure out the cause and have a clear complexionㅠㅠ Thank you always for your kind answers!!!