Where it lives
On a TIE card it leads with an E and a string of digits — think E00000000 — printed on the front or the reverse of the card.
On the green EU certificate it shows up as the IXESP or C-number reference. On the older A4 versions, look near the top for a line tagged "Nº de soporte".
What it does for you
It is the key that confirms your identity on digital services — Cl@ve, the immigration sede electrónica, plenty of Balearic regional portals. Leave it out and the online procedure simply will not go through, which is why it is worth knowing before you sit down to file anything.
In Ibiza
Most the número de soporte requests across the Balearic Islands pass through the Ibiza office. We know exactly what they ask for — and we accompany you, whether you live in central Ibiza or out in Sant Antoni de Portmany.