The K-1 visa, often known as a fiancé (e) visa, is a non-immigrant visa designated for foreign fiancés (e) of US residents. 

If you meet the following criteria, you can bring your future fiancé(e) to the United States on a K-1 visa:

1. You are a citizen of the United States.

2. You and your partner want to marry within 90 days of your partner's arrival in the United States on a non-immigrant K-1 visa.

3. You and your partner have no legal impediments to marriage (all prior marriages have been legally dissolved through divorce, death, or annulment).

4. You and your partner met in person at least once in the two years preceding the filing of the petition. You may request an exemption from this criterion if you can demonstrate that a personal meeting: contradicts traditions or long-established social conventions in your partner's nation; or puts you in a difficult situation as a U.S. citizen applicant.

The following are the procedures for acquiring a nonimmigrant visa K-1:

1. US citizens must file Form I-129F (Petition for Alien Fiancé (e)) with USCIS on behalf of their foreign groom or bride. He must show proof that they both intend to marry within 90 days of the overseas partner's arrival in the United States.

2. The petition will be reviewed by USCIS, which will decide whether to approve or deny it. If the petition is authorized, it will be forwarded to the consular department of the nation in which the foreign partner resides.

3. A foreign bride or groom must apply for a K-1 visa at the consular department of the United States Embassy or Consulate in their home country. They must produce different documents, such as a medical certificate, a certificate of non-judiciality, and financial assistance from a US citizen, to demonstrate that they will not be a burden to the state once they arrive.

4. After applying for a K-1 visa, the foreign bridegroom or bride must attend a consular interview. The interviews will ask about their relationship, marriage intentions, and other questions aimed at confirming the relationship's legitimacy.

5. Following the interview, the consul will determine whether to grant or deny a K-1 visa. If the visa is granted, the foreign partner will be issued a passport that includes a visa and will be permitted to visit the United States.

6. A foreign bridegroom or bride must marry a U.S. citizen within 90 days after arriving in the United States on a K-1 visa. They can then apply to change their status and obtain a permanent green card.

If you are already married, plan to marry outside the United States, or your bridegroom is a legal resident of the United States, your spouse or bride is ineligible for a K-1 visa. 

If your future spouse has a child (under the age of 21 and unmarried), that child may be entitled to enter the United States on a temporary nonimmigrant visa K-2. To bring a child to the United States, you must fill out the I-129F form with the names of your future spouse's children. A youngster is not permitted to enter the United States before his or her parents (the future bridegroom or bride).

If your prospective spouse's children hold a K-2 visa, they can apply for a green card by submitting an I-485 form to USCIS. Non-immigrant K-2 children, on the other hand, must remain unmarried in order to be eligible for a green card. Non-immigrant K-2 children must apply for a green card at the same time as or after their future spouse.

Recommendations and advice:

1. Because acquiring a K-1 visa can take some time, it is best to start planning ahead of time. 

2. You must offer proof of a genuine and serious connection with a US citizen. Include photos, letters, checks for joint expenses, and other evidence that demonstrates your affection and the strength of your connection.

3. The interview is a key element in the application process for a K-1 visa. Expect questions about your relationship history, future goals, and why you want to marry.

4. Stick to the timeframes for submitting documents and conducting interviews. Failure to meet deadlines might result in delays or even rejection of a visa. Be organized and make time for yourself.

K-1 and K-2 non-immigrant statuses cannot be prolonged. If you do not marry within 90 days, your fiancé(e) and his/her children will be forced to leave the country. If they do not leave the country, they will be in breach of US immigration laws and may face deportation.