Why am I charged a service fee?

Could you please explain why I am being charged a service fee for using this platform? I understand that there are costs associated with maintaining and operating the system, but I would like to know more about how this fee is calculated and what specific services it covers. Is it a flat rate or does it vary depending on the transaction amount or type? Also, are there any ways to reduce or avoid this fee in the future? Thank you for your clarification.