English Japan
Conditional Residents
For those of you who obtained your permanent residency through marriage to a U.S. citizen and if you were married less than two years at the time the permanent residency was granted or obtained a green card through investment, the USCIS issues a conditional green card that is valid for only 2 years.  If this applies to you, you have to file a Petition to Remove the Conditions of Residence within the 90 day period preceding the expiration date of your 2 year green card. If you fail to file on time, your conditional resident status will be terminated, and you will be subject to deportation.
Income Tax
Permanent residents are required to file U.S. federal tax returns as “residents” under taxation law, even if you reside outside the U.S. and pay income tax to a foreign government. Otherwise you may be deemed to have abandoned the green card. If you work outside the U.S., it is essential that you consult with accountants or tax attorneys who are competent in this field.
Change of Address

All non-U.S. citizens who are within the U.S. are required to keep the USCIS informed of their current address within 10 days from the date of such change by filing the Form AR-11.  If you are subject to Special Registration, the Form AR-11SR is the appropriate form. You may download free forms from the official website of the USCIS at The only aliens exempt from this requirement are diplomat (visa status A), official government representatives to an international organization (visa status G), and certain non-immigrants who do not possess a visa and who are in the U.S. for fewer than 30 days.

Application to Replace Permanent Residence Card
This is an application to replace a lost or destroyed card, to update a card after change in your biographic data, to replace a card that is expiring or to replace a card due to other circumstances. 
Reentry Permit
If you are planning to be outside of the U.S. for more than a year, a re-entry permit is a proper travel document to apply while you are physically present in the U.S.  If you are outside of the U.S. continuously for more than a year, your green card becomes invalid to re-enter the U.S. and you may be deemed to have abandoned your permanent residency status.
Applying Green Card for Family
Permanent residents can file an immigrant (green card) petition on behalf of their spouses and unmarried children. However, permanent residents’ spouses and children are subject to the availability of visa numbers, so they usually have to wait more than 5 to 7 years before they obtain permanent residency status. Permanent residents are not eligible to file immigrant petition on behalf of their parents. In order to sponsor green card for your parents, you have to be a U.S. citizen and must be at least 21 years old.
Permanent residents are eligible to apply for U.S. citizenship up to 90 days before their 5 year anniversary (or 3 year anniversary if you are married to a U.S. citizen) from obtaining permanent residency status. Among other things, they have to demonstrate that they have been physically preset in the U.S. for periods totaling at least half of that time, they are a person of good moral character, have an understanding of the English language, and have knowledge and understanding of the fundamentals of the history and government of the U.S.
U.S. citizens can file green card application on behalf of not only their spouses and children, but also their brothers and parents. In some cases, it is possible to receive green cards for U.S. citizens’ parents, spouses and unmarried children under 21 within 4-6 month from the filings, even if their authorized stay had expired long time ago.

Permanent residents could lose their residency status, by committing crimes for example, or even become subject to removal proceedings. On the other hand, U.S. citizens are entitled to live in the U.S. permanently without being subject to deportation. They are also permitted to vote, and are eligible to receive federal scholarships, grants or public benefits which are not provided to permanent residents. Permanent residents may have to pay more tax under gift and inheritance tax rules.

Selective Service
Almost all male U.S. citizens and most of the male foreign nationals living in the U.S., who are 18 through 25, are required to register with the Selective Service.  You can register online from the official website at Non-immigrants who are in the U.S. legally are generally not required to register.