You can request a postal vote on the website, without having to go to a post office in person.
Who can use the application to submit an electronic request for a postal vote?
It cannot be requested by voters who are residents in Spain and are temporarily abroad, or by voters who are residents abroad and request it from their country of residence.
You will need to have an IDCAT certificate (how to get one), T-CAT, electronic DNI (get electronic DNI) or a valid digital certificate.
The Electoral Census Office must approve the request, so that it can send the documentation for voting to the address you have indicated in your request.
It can be requested from the date of the announcement until 4 February 2021.
You can then exercise your right to vote from your own home by handing the envelope with your vote to the postal worker on the day they come to take your documents.