You can apply for this at the ayuntamiento. Also online in English at https://alicante.avanzagrupo.com/en If you are on the Padron you are advised to do it through the town hall to get more benefits. You will need a photo.
For Benidorm council book appointment (Cita Previa) at. https://benidorm.org/es/ayuntamiento/concejalias/atencion-al-ciudadano/cita-previa. Chhose Otro Tramite Sin Registro and choose nearest office.