Los modelos de Hacienda, o modelos tributarios, are a headache for many taxpayers due to the sheer number and specific purpose of each one. In this article, we aim to help you understand the purpose of each form in an easy and comprehensible way. This guide provides an overview of the standard forms for self-employed and SMEs. Please note that filing the correct form is only half the battle; ensuring the data is tax-compliant requires professional oversight to avoid costly AEAT audits. Tax deadlines in Spain typically fall between the 1st and 20th of the month following the quarter. However, deadlines can vary based on public holidays and specific taxpayer profiles. We recommend confirming exact dates each quarter. While these forms are public, incorrect entries can trigger automatic penalties. Our monthly plans include the preparation, optimization, and submission of all relevant forms, ensuring you never miss a deadline or a deduction. This list is not exhaustive. Depending on your specific business activity (e.g., international trade, hiring employees, or renting office space), additional forms may be required. Innotaxes is not responsible for penalties incurred due to self-management based on this general guide.