What is the amendment fee?

Excuse me, could you please clarify what the amendment fee entails? Is it a fee that is imposed when changes are made to a transaction or a contract? How does this fee differ from other fees associated with cryptocurrency transactions? Additionally, is the amendment fee a standard fee across all platforms or does it vary depending on the cryptocurrency exchange or wallet being used? Lastly, how does one go about paying this fee and are there any specific requirements that need to be met in order to avoid incurring the amendment fee? Thank you for your time.