You do not have to register to use Surf. Surf is a tool for interacting with the Everscale blockchain and does not request or collect any personal data.
When creating a new Surf wallet, you need to read the Decentralization Policy and explicitly agree to follow it.
To read the Surf Decentralization Policy:
On the main screen of the application, tap the Surf icon in the upper left corner.
Tap Decentralization policy.