If you are a fiancee or spouse of a US Citizen, you will need to obtain a K Visa in order to enter the U.S. while you wait for your Immigrant Visa petition to be processed. There are four K Visas:
K-1 for fiancees
K-2 for dependants of fiancees
K-3 for spouses
K-4 for dependents of spouses
K-1 requirements
The US citizen must file the Petition for Alien Fiancé(e), Form I-129F with the Department of Homeland Security's U.S. Citizenship and Immigration Services (USCIS) office that serves the area where you live.
Once the petition is approved and sent to the embassy or consulate of the fiancees country of citizenship, the fiancee will need to take a medical exam and must provide the following information:
A passport valid for travel to the United States and with a validity date at least six months beyond the applicant's intended period of stay in the United States.
Birth certificate
Divorce or death certificate of any previous spouse for both the applicant and the petitioner
Police certificate from all places lived since age 16
Evidence of financial support (Form I-134, Affidavit of Support may be requested.)
Two Nonimmigrant Visa Applications, Form DS-156 (A Form DS-156, prepared in duplicate.)
One Nonimmigrant Fiancé(e) Visa Application, Form DS-156K
Two nonimmigrant visa photos (each two inches 50 X 50 mm square, showing full face, against a light background)
Evidence of a fiancé relationship
The consular officer may ask for additional information according to the circumstances of the case.
You must get married within 90 days of your fiancé(e)’s entry into the United States.
The K-1 visa allows a fiancé(e) to enter the United States one time only. If you leave the United States after entering on a K-1 visa, you may not re-enter on the same visa. If you want to leave and re-enter the United States, you should apply with Form I-131 Application for Travel Document to the USCIS office that serves the area where you live for advance parole to return to the United States.
As a K-1 visa holder you may file Form I-765 Application for Employment Authorization with the USCIS office that serves the area where you live for a work permit (employment authorization document).
K-2 requirements
The child of a fiancé(e) may receive a derivative K-2 visa from his/her parent’s fiancé(e) petition. You, the American citizen petitioner, must make sure that you name the child in the I-129F petition. After the marriage of the child’s parent and the American citizen, the child will need a separate form I-485 Application to Register Permanent Residence or to Adjust Status.
The child may travel with (accompany) the K-1 parent/fiancé(e) or travel later (follow-to-join) within one year from the date of issuance of the K-1 visa to his/her parent. A separate petition is not required if the children accompany or follow the alien fiancé(e) within one year from the date of issuance of the K-1 visa. If it is long than one year from the date of visa issuance, a separate immigrant visa petition is required.
Remember that the child must be unmarried and the stepparent/stepchild relationship must be created before the child reaches the age of 18.
K-3 requirements
The application for the nonimmigrant visa for spouse (K-3) who married a U.S. citizen must be made and the visa issued in the country where the marriage took place.
The first step is to file a Petition for Alien Relative, Form I-130 for your spouse (husband or wife) to immigrate to the United States. This must be done before applying for a K-3 Visa.
In general the following will be expected:
A passport valid for travel to the United States and with a validity date at least six months beyond the applicant's intended period of stay in the United States.
Birth certificate
Marriage certificate
Divorce or death certificate of any previous spouse for both the applicant and the petitioner
Police certificate from all places lived since age 16
Evidence of financial support. A completed Form I-864 Affidavit of Support from petitioner/ sponsor is required.
Two copies of form DS-156, Nonimmigrant Visa Application
One DS-156K, Nonimmigrant Fiancé(e) Visa Application form
Two non-immigrant visa photos.
Proof of the marriage and the husband/wife relationship
As a K-3 visa holder, you can file form I-765, Application for Employment Authorization with the USCIS that serves the area where you live for an employment authorization document (work permit).
K-4 requirements
Children do not need separate Petition for Alien Relative, I-130 petitions, but you, the petitioner, must take care to name all your children on the Petition for Alien Fiance, I-129F petition, in order to avoid further complications.
You must file separate I-130 immigrant visa petitions for your children before they qualify for permanent residence. When they adjust status in the United States, they must file Form I-485 Application to Register Permanent Residence or to Adjust Status with the USCIS Office that serves the area where you live.
Remember that the child must be unmarried and under 21.
For more information, or for help determining and obtaining the right VISA for you, please consider a legal consultation.