Two-Step Process: The process typically involves two steps:

• Petition for Alien Relative (Form I-130): The U.S. citizen or permanent resident files this petition with USCIS to sponsor their foreign spouse.
• Consular Processing or Adjustment of Status: Once the petition is approved, the foreign spouse either goes through consular processing at a U.S. embassy or consulate abroad, or adjusts their status within the U.S. (if they are already in the country legally). 

Conditional Permanent Residency: If the marriage is less than two years old when the foreign spouse enters the U.S., they will receive a conditional permanent resident status. After two years of marriage, they must file a petition to remove the conditions.   

Evidence of Bona Fide Marriage: To prove the authenticity of the marriage, couples may need to provide evidence such as joint bank accounts, joint leases, shared addresses, photographs, and testimony from friends and family.

Processing Time: The processing time for marriage-based visas can vary depending on various factors, including USCIS backlogs and individual circumstances.  

It’s important to note that marriage-based immigration can be complex, and it’s advisable to consult with an immigration attorney to ensure a smooth process.