You can consult it on the e-Office, using the Duplicate Affiliation Document Service Via SMS, if you have previously provided the Social Security General Treasury with your mobile telephone number. In this case, after requesting a code that you will receive by SMS, you can obtain, print and/or consult the duplicate showing your Social Security affiliation number immediately, and download it. Username + Password (permanent Cl@ve) With digital certificate Finally, you can also find your Social Security affiliation number by going to any Social Security Office where they will give you the number and a duplicate affiliation document