The first thing that needs to be clarified is whether your foreign born fiancé is actually here in the United States or abroad. For purposes of this article, let's assume that he/she is not residing here but living abroad in his/her native country. Under these circumstances, you can't technically file for his/her her "green card," or permanent residence until the both of you wed and establish a legal relationship as spouses. However, this does not mean that you are out of options. There is K-1 Visa or Fiancé Visa, and there can be any number of reasons why the two of you might want to pursue such a visa instead. For example, it may be that you are just not yet ready to wed abroad, or maybe you cannot make plans to travel abroad to get married. Under certain circumstances, it may be even be quicker for your loved one to get here on such a visa as opposed to a marriage-based spouse visa. Now you would only want to consider this option if you are not yet married and more importantly, will not get married while the process is pending, which can take many months. Unfortunately, if you were to sponsor your fiancé for a K-1, and then get married before the visa is granted, your fiancé would no longer be eligible for the fiancé visa since he/she is no longer your fiancé. As logical as this sounds, many people out of frustration and poor planning, have made this very mistake and have had to start an entirely new and different process to bring their loved here to America. Also, the both of you must, of course, be legally free to marry. In other words, if your loved one is technically still married to someone, he/she cannot legally marry you until he/she has first dissolved the current marriage. You would not want to initiate the fiancé immigration process until the divorce is legally finalized. Additionally, USCIS generally requires that proof that the both of you have met within the past two years. While there are limited exceptions, the best course of action would be to actually meet and retain proof that you have met the person you intend on spending the rest of your life with.
The purpose of the K-1 visa is to allow your fiancé to enter into the United States for the specific purpose of getting married to you. Once the visa is granted, and your loved one arrives here, you will have to wed within ninety days. Be warned: the consequences of not getting married within the ninety days can be extremely severe. Another thing to keep in mind is that the K-1 is a temporary visa. It does not, by itself, confer permanent residence on your fiancé. In fact, he/she will only be admitted for a temporary period of time, which will legally expire. Do not make the mistake of assuming that once your fiancé arrives here on a K visa, the immigration process is concluded. Do not also make the mistake of assuming that your fiancé can start working right away and applying for his/her social security card. He/she must apply for work authorization on Form I-765 if there is a desire to seek employment within the United States. Remember, the fiancé petition only gets your loved here. You are only halfway there. After the wedding is concluded, your fiancé must then take steps to actually apply for permanent residence.