All men between the ages of 18 and 25 must apply for the US selective service as a Lawful Permanent Resident of the United States of America. Registering for the selective service can be done online with the Selective Service System after the applicant receives their Green Card and Social Security Card. Recruiting for the Selective Service only comes into force if the USA is experiencing a serious crisis.
All US citizens and permanent residents, as well as some temporary US work visa holders, are required to apply for a nine-digit Social Security Number (SSN). The SSN will be issued on a physical Social Security Card (SSC). This number is very important in the USA for identification purposes. From filing taxes to applying to university, you are required to have a Social Security Number.
The husband or wife of a US visa applicant. The marriage must be legal under US marriage laws. Spouses in same-sex marriages who married under US law also qualify for a Green Card. Co-habitation and civil unions are not recognized in the USA as marriages.