Block 8 – Employee's Social Insurance Number. In this block, enter the employee's 9-digit Social Insurance Number (SIN).Looking for a local office? Use one of our online services and save yourself a trip! Fill out all sections COMPLETELY and to the best of your ability. Your application will be used as part of the examination process and,. Required for account owner: Full name, Social Security number (or ITIN),1 date of birth and street address (include any APT. It is not illegal for an employer to ask you for your social security number (SSN). HOWEVER you are in no way obligated to provide your SSN. When filling out Form I-485 or Form I-765, all you need to do is check "yes" when asked whether you would like to receive a Social Security card.