A K1 visa allows a non-US citizen to enter the US in order to marry a US citizen. This marriage must take place within 90 days of entering the country. Once the marriage has taken place, however, the K1 visa holder needs to start the process of adjusting status by filing USCIS Form I-485 (Adjustment of Status). The US citizen in the relationship must also file an affidavit of support at the same time, avowing that the non-US spouse will not become a burden on the US government by applying for public assistance. The affidavit of support basically ensures that the US spouse financially supports their new spouse.
Once the USCIS has approved the I-485 form, the non-US spouse will be granted a conditional green card. This card allows the new spouse to work and live in the US as a conditional permanent resident for up to two years. Within 90 days of this two year date, however, the couple must apply to remove the conditions from the green card. This is done by filing USCIS form I-751. Once the USCIS approves this petition, the non-US spouse will be given a regular green card, which confers permanent residency. The spouse will then be allowed to live and work in the US permanently and will be eventually apply for US citizenship after meeting residency requirements and all other requirements for citizenship.
As part of the adjustment of status, the K1 visa holder will need to be in the US in order to apply or adjustment of status. As well, the person adjusting status will need to pay a filing fee to the USCIS when submitting the correct forms and will need to submit photos with the application. In addition, the person applying for adjustment of status will generally need to submit to a medical exam and will need to show evidence that they entered the US legally with a Form I-94 (Arrival-Departure Record).
Another issue when applying for adjustment of status from a K1 visa is the issue of immigration fraud. In the US, it is illegal to marry a US citizen just to get immigration status. Immigration officials check carefully to ensure that anyone applying for adjustment of status from a K1 visa is in a valid marriage. Therefore, if you are adjusting status after marrying a US citizen, you may wish to have evidence of your relationship, including photos of family events. If you have been accused of immigration fraud or if your marriage may not last or has already ended by the time you try adjusting status, you may wish to speak to a qualified US immigration attorney before applying for your green card.