If the 210 form filing corresponds to a self-assessment of two spouses' incomes generated on property sales who are opting to make a joint tax return, access to the form and signing of the form will require the digital certificate of one of the spouses. The other spouse and holder of the tax return will have to authorise the other party to carry out the procedure on their behalf by registering the corresponding authorisation.
For this reason, in the procedures page of the Form 210 a direct link has been provided to the page for managing this authorisation.
Whilst online filing of form 210 requires identification by digital certificate of DNIe, the second holder can make the authorisation both with the digital certificate or with the Cl@ve PIN.
Once identified, they will have to state the tax code of the party two whom the 210P procedure is to be authorised. The authorisation may be set up with a limited term, by stating an end date in the field "End date of Authorisation", or it can also be unlimited, until renewed or cancelled by one of the parties, in which case this field should be left blank. You should also tick the box for personal data processing authorisation.
After the authorisation is in place, the tax return can be filed, making sure to provide the proper data for joint filing: type of Income, code 28 and the section "Based on the gross tax base", Code C (spouse), participation rate of the taxpayer and spouse and identification of the spouse.