5.3.1. How does one voluntarily adopt SII?
There is the possibility of joining the SII voluntarily, opting at any time by submitting form 036 (boxes 143 and 532), being included from the day following the day on which the settlement period ends in which said option was exercised. .
EXAMPLE :
A company that opts for the SII, presenting form 036 on February 10, 2021, will be included in the system from April 1, 2021.
The information related to invoices issued and received before April 1 will have until December 31, 2021 (inclusive) to send them. Those issued or received later will be sent within the specific SII deadlines already mentioned.
Taxpayers included in the SII are not required to submit the Annual Declaration of operations with third parties, form 347 New window , and the annual Summary Declaration of Value Added Tax, model 390 New window .
This exemption entails the necessary completion of additional boxes in the self-assessment corresponding to the last settlement period of the year.
