How to access Pre303?

The Pre303 service is a support service offered when submitting the model through the AEAT electronic office (via form).　

You can access it in your own name (with Cl@ve PIN, DNI and electronic certificate) or authorize a third party to access it on your behalf.　

Additionally, some of these services will also be available to all taxpayers as specific, independent services. They can be found in the Pre303 section.