Your H1B approval notice, your complete I-129 petition (including LCA that was filed by your employer for your H1B (ask the company lawyer to certify this), company letter that you are employed by them and your skill set and salary should be mentioned, all the pages of your passport, photographs of your company (exterior and interior) recent 4-5 pay stubs, send the copy of your recent I-94 ( both the sides)Marriage certificate
and what tt tt wrote
She has to fill up form, pay the fees attach her photograph (new photo specification). For more info go to US consulate site and read.