Soptify as a partner

[JordiJR]

Good morning!

We are developing a mobile application (Android & iOs) where each user should be able to select and display favorite songs.
How to use the Spotify API I don't think it will be a problem for our development team.
My question is regarding whether there is a cost for the service and, if so, the amount thereof.
Likewise, the matter of copyright, I understand that it falls on Spotify or also affects us.
On the other hand, would it be possible to establish a relationship with Spotify as a partner?
Who should we talk to?

Kind regards
Jordi