If you do not have an electronic certificate, you can request an individual electronic certificate from the FNMT (Instructions at https://www.sede.fnmt.gob.es/certificados/persona-fisica).

One of the steps to obtain the certificate is identity verification at the authorised office that is most convenient for you (http://mapaoficinascert.appspot.com/). Please note that these offices may require an appointment.

One of these offices, where an appointment is not necessary, is the General Registry of the U.P.M. Location and opening hours.