I am an US citizen living in the US.  My fiancée lives in Taiwan and is a Taiwan national.  We plan on getting married and living together in America.  I am confused about the difference between a K1 or K3 visa and an IR-1 or CR-1.  Which is faster?  Should we apply in the US or in Taiwan?  Until then can my fiancée travel using her B1/B2 visa?

If you plan to get married in Taiwan:  Your wife should enter the US as an immigrant instead of as a tourist as she intends to stay permanently in the US.  She should not travel using her B1/B2.  If you are currently living in the US you will need to initiate the process by filing an I-130 on behalf of your wife with the Citizenship and Immigration Services (CIS) district office having jurisdiction over the petitioner’s current or intended residence in the US.  The CIS Internet website (www.uscis.gov) has complete information on Service Center jurisdiction. 

Once the petition is approved, she will be scheduled for an appointment at AIT to apply for an IR-1 or CR-1 immigrant visa.  These are the same, except that the CR-1 visa indicates conditional status.  Once you have been married for two years, you can apply to have the conditional status removed.  If you have already been married for two years, she can apply for an IR-1 without going through the conditional period.  

If you plan to get married in the US:  Your fiancée should enter the US with a fiancée visa.  The purpose of the K1 fiancée non-immigrant visa is for the alien to enter the US to conclude a valid marriage with the American citizen petitioner within ninety days after admission.  All K visa petitions must be filed with the CIS district office having jurisdiction over the petitioner’s current or intended residence in the United States.  After the petition is approved, your fiancée will be scheduled to appear for an interview at AIT in Taiwan. 

A K3 visa is meant to be a speedy mechanism for the spouse of a US citizen to join the US citizen spouse and obtain the immigrant visa/status in the US.  The purpose of the K3 non-immigrant visa is for the spouse of US citizen to enter the US as a non-immigrant to continue to pursue the immigration process to await approval of an I-130 immigrant visa petition which is pending by the US Citizenship and Immigration Services (CIS).  Your wife must apply for a K3 visa at the visa issuing post in the country where the marriage took place, if the marriage occurred outside of the US.  In order to obtain K3 status for an alien spouse, the alien must be married to a US citizen who has filed an IR-1/CR-1 I-130 petition on behalf of the alien.  The US citizen petitioner must also file a second petition, the I-129F, with CIS for a non-immigrant visa (K3) on behalf of the alien spouse if the initial IR-1/CR-1 I-130 petition is still pending at the CIS office.