What is your immigration status? Generally you can begin the spouse immigration process by properly filing an I-130. I highly recommend seeking a private consultation with an experienced immigration attorney. My office offers free consultations.
Not a document, a first move, would be a more appropriate quesiton. Visiting www.uscis.gov and learning about the process. Hiring a competent immigration attorney once you have realized how not easy it is.
The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter,not should it be viewed as establishing an attorney client relationship of any kind.
Need more facts. The best thing for you to do is consult an immigration attorney to evaluate your options.
Alexus P. Sham email@example.com (917) 498-9009. The above information is only general in nature and does not constitute legal advice. It does not create an attorney-client relationship.