Does the concordat agreement need to be notarized?

[DuuNSo]

Hello, I want to commission a music piece for my website, and I have specified the areas where I will use it to my freelancer friends. They provided me with a price and mentioned that the agreement will be sent to my address. I asked them if it will be notarized because I consider it as a notarized document, but they said that the agreement will not be notarized. I got confused, so I researched it, and the websites also mention that it will be notarized. I am really confused, and I would be really happy if someone could clarify this for me.