How do I change last name to married name when applying?

[stefan y karen 23]

She came into the country on a K-1 Visa with her maiden name. We put her married name on the marriage certificate. What do I put on the I-485? Do I put her married name or her maiden name on the forms? I would prefer to put her married name but I do not want to screw up the process.

Thanks for your help.

[Lainie B 465]

Use her married name. The marriage certificate is the legal proof of name change