1. File I-130 Petition for Alien Relative (with I-130A supplement) with USCIS.  (5 to 8 months)

http://www.uscis.gov

https://www.uscis.gov/i-130

Case processing times: https://egov.uscis.gov/processing-times/

2. Upon approval of I-130 petition, file gets transferred to National Visa Center (NVC). Petitioner (U.S. citizen) submits Civil Documents and Affidavit of Support to NVC; Immigrant Visa applicant (foreign spouse) completes DS-260 Immigrant Visa application online.  (1 to 3 months)

https://travel.state.gov/content/travel/en/us-visas/immigrate/national-visa-center.html

Civil documents: https://travel.state.gov/content/travel/en/us-visas/Visa-Reciprocity-and-Civil-Documents-by-Country.html

3. After NVC completes processing, file is sent to U.S. embassy or consulate abroad for foreign spouse’s application and interview for an Immigrant Visa.  (1 to3 months)

U.S. Embassies and consulates worldwide: https://www.usembassy.gov/

Preparing for the interview: https://travel.state.gov/content/travel/en/us-visas/immigrate/the-immigrant-visa-process/interview.html

The medical examination: https://travel.state.gov/content/travel/en/us-visas/immigrate/the-immigrant-visa-process/interview/interview-prepare/medical-examination.html