First, proof is required that your foreign spouse is married to you, a US citizen. Then you must file form I-130 (Petition for Alien Relative).Make sure it is completely and accurately filled out. After finishing and signing, pay the $535 filing fee. Follow the instructions here Direct Filing Addresses for Form I-130, Petition for Alien Relative to find out where you should ship the form, depending on where you live.Fiancu00e9es or spouses of the U.S. citizens and their unmarried children (K visas) has more information on k-visas, should you need it.