Why am I being charged an international transaction fee?

Excuse me, I'm a bit confused about the international transaction fee that's been charged to my account. Could you please clarify why this fee has been imposed? Is it because the transaction involved a foreign currency or is it a standard charge for all cross-border payments? Additionally, I'd like to know if there are any ways to avoid or reduce this fee in the future, perhaps by using a different payment method or selecting a specific currency for the transaction. I appreciate your help in understanding this matter.