You will need to attach one copy of any W-2s or 1099-Rs that were not included in the original return to the front of the 1040X.
You will also need to include any forms that were added or changed as a result of the amendment. For instance, if you qualify for a retirement savings credit as a result of adding the new income, then you would include From 8880. If you itemized and had state taxes deducted from your W-2, you will need to send the revised Schedule A. Compare the original return with the amended return to see which forms are new and which have changed.
Your amended return will generate a revised Form 1040. DO NOT send the 1040, only the 1040X.
You will both need to sign and date the return before you mail it to the IRS.
