What is the IV fee?

Excuse me, could you please clarify what the IV fee is? I'm a bit unfamiliar with the terminology in the cryptocurrency and finance world, and I'm trying to better understand the various costs associated with transactions. Is the IV fee a one-time charge, or does it apply to each transaction? Also, how does the IV fee compare to other fees that might be involved in a cryptocurrency transaction? I'd appreciate any information you can provide to help me better navigate this complex landscape.