Assuming you are not yet married, your United States citizen fiancé could file a fiancé visa petition on your behalf. This process is started by filing Form I-129F with the required supporting evidence. This would allow you to seek a visa that allows you to enter the country for the purpose of marrying and seeking permanent residence. If you are already married, your spouse would need to file an immigrant visa petition on your behalf. This process is started by filing a Form I-130 with USCIS.
Answered on Nov 30th, 2015 at 4:01 PM