What is a securitization fee?

Excuse me, could you please elaborate on what exactly a securitization fee entails? As I understand it, it's a fee associated with the process of converting assets into securities, but I'm not entirely clear on the specifics. Is it a one-time fee? Does it vary depending on the type of asset being securitized? Additionally, who typically pays this fee, and how does it impact the overall cost of the securitization process? I'd appreciate any insights you can provide.