Most immigrants seek green cards because green cards offer US permanent residency and therefore fewer conditions. With a green card, you can travel freely in the US, leave and return to the US, and work in the US. However, there are different green cards and some do not offer the same level of freedom from restrictions. As their name suggests, conditional green cards come with more green card conditions than traditional permanent residency cards.
There are in fact two types of green cards that come with green card conditions: Green Card through investment and Green Card through marriage. These green cards are conditional for a period of two years. Conditional green cards were created by the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRAIRA) and the Immigration Reform and Control Act of 1986 (IRCA).
A Green Card through investment is available to immigrants who invest money or establish a business in the US that helps the US economy. A Green Card through marriage is issued when a US citizen or permanent resident marries someone who does not have status in the US.
Once the two years of a conditional green card are expired, the green card holder can no longer live and work in the US. Before this expiry date, therefore, holder of a green card will usually want to remove conditions on their green card and become a full permanent resident of the US. To do this, at least 90 days before the green card expires, it is important to file a Petition to Remove Conditions on Residence (USCIS form I-751) or Petition by Entrepreneur to Remove Conditions (USCIS form I-829). You will use form I-751 if you have a Green Card through marriage and form I-829 if you have a conditional Green Card through investment.
Once you have applied to remove conditions from your green card, your green card will be renewed for one year conditions while you application is pending. In cases of Green Card through marriage, especially, applicants will have to prove that the marriage is not fraudulent. This means that they may have to meet with USCIS authorities, may need to submit documentation of a shared life, and may need to submit letters from friends and employers proving their marriage. Once the USCIS approves the application, a permanent residency card (minus green card conditions) will be issued. In most cases, the new green card is sent by mail.