Here are majoy parts.
a currently dated letter or other evidence from your intended permanent employer that indicates your current position, if any, your proffered position, the date you began employment and the proffered salary or wage. The letter must indicate whether the terms and conditions of the employment-based immigrant visa petition (or labor certification) continue to exist.
(If change employer, ... need the proof of same job, don't remember exactly)
Provide a copy of your 2005 W-2 wage earning statement and federal income tax return.
Provide a copy of your most recent pay voucher. The document that you provide must identify both you and your employer by name, and specify your gross/net pay, income received year-to-date, income tax deductions withheld, and the length of the pay period.
Provide a copy of a CURRENT photo identity document that possesses your name and date of birth, e.g., driver’s license, national ID, passport or visa renewed or issued within the last 30 days, etc.