Starting, modifying, or closing an economic activity in Spain requires formal communication with the Spanish Tax Agency (AEAT). Before issuing your very first invoice or when closing down your freelancing trade, you must file a census declaration using either Form 036 (*Modelo 036*) or its simplified counterpart, Form 037 (*Modelo 037*).
Understanding which form to use and keeping your tax census records up to date is essential to prevent penalties and administrative discrepancies.
Form 036 vs. Form 037: Main Differences
Form 036 is the comprehensive census statement. It is mandatory for all legal entities (such as SLs and corporations), non-resident entities, and individuals who do not qualify for the simplified procedure (such as those applying the special VAT cash accounting scheme or carrying out distance sales within the EU).
Form 037 is the simplified option tailored for most sole traders and freelancers. You qualify to use Form 037 if you meet the following conditions:
* You are an individual tax resident in Spain with a definitive NIE/DNI.
* You fall under standard VAT regimes (general regime, equivalence surcharge, or simplified regime).
* You are not involved in complex distance selling or special non-resident schemes.
If you are setting up your freelance business, make sure to read our complete manual on how to register as a freelancer step by step to coordinate AEAT registration with the Social Security system (RETA).
Registration, Changes, and Deregistration Deadlines
1. **Initial Registration (*Alta*):** Must be submitted before actually commencing operations or purchasing any deductible business assets. Here you establish your business economic activity codes (*IAE*), personal income tax system (direct estimation or modules), and applicable VAT regime.
2. **Modification (*Modificación*): You have a one-month** deadline from any change, such as moving your fiscal domicile, setting up an additional office, or adding secondary business activities.
3. **Deregistration (*Baja*): Must be submitted within one month** after completely ceasing your economic activity. Completing your tax deregistration is required before cancelling your social security contributions.
Census Alignment and VeriFactu Compliance
Your census filings dictate the operational parameters of your invoicing system. Under the VeriFactu framework—mandatory by January 1, 2027 for corporations and by July 1, 2027 for freelancers and sole traders—invoicing data will be audited against your official AEAT census profile.
If you still rely on spreadsheets or outdated desktop programs, modernizing your setup is crucial. Businesses frequently need to importar Excel a VeriFactu or migrate existing ledgers by deciding to importar Sage 50, importar Factusol a VeriFactu, or importar Holded. For larger companies and developers, setting up a pasarela VeriFactu para software via an API VeriFactu or direct integración ERP VeriFactu guarantees that tax codes, series, and VAT exemptions match census declarations seamlessly.
Fakturia.es provides a modern cloud invoicing platform fully compliant with the Spanish Anti-Fraud Law and VeriFactu technical requirements, ensuring that your tax census setup and ongoing invoicing stay perfectly aligned.