Yes, marriage is allowed: You can legally marry in the U.S. on a B2 visa.

Marriage doesn’t give legal stay or work rights by itself.

Change of status must be filed: If staying, apply for a green card based on marriage.

You can get married in the US on a B-1/B-2 tourist visa or visa waiver program, but be aware that applying for adjustment of status afterward may raise questions about your original intent, potentially leading to scrutiny or denial if deemed visa fraud