Guides
Step by step: what you do with the Agencia Tributaria and what Trimestria does afterwards. Every guide cites the official page it rests on and the date the Agencia gives it.
Before you startCl@ve, the digital certificate and what you need to act online.1 guide
- How to get Cl@ve, even without going to an officeBy letter, by video or in person, with your DNI or NIE. What the Agencia says about the level of Cl@ve, and what it does not say.
Giving Trimestria accessThe apoderamiento with the Agencia: how it is granted and how it is withdrawn.2 guides
- How to grant Trimestria the apoderamiento at the AEAT's SedeWith your certificate, your DNIe or your Cl@ve, in about ten minutes. Trimestria confirms it afterwards.
- How to revoke Trimestria's apoderamiento at the AEAT's SedeTwo different steps: withdrawing the authorisation in Trimestria and revoking the apoderamiento at the Sede. What Trimestria stops doing from each.
Filing your returnsYour first 303 with Trimestria, and what stays in your hands.1 guide
- Your first modelo 303 with TrimestriaWhat to check before you confirm, the four ways to file it, the NRC and the receipt, and what to do if something does not add up.
Looking for something else?
The questions on the front page answer the general things; for your own case, write to us.
The dates
«Reviewed on» is the day we re-read the whole guide. The Agencia's date is the one its own page prints at the bottom, and we cite it as it stands.