The most common reference for "104X" is the . Taxpayers use this form to correct an individual income tax return that has already been filed for a specific year.

If this is not related to taxes, "Abv" may refer to data or a specific software version identifier (e.g., version 104x).

: If you are looking for the federal (IRS) version of an amended return, that is Form 1040-X .

Are you trying to into a specific program (like Excel or Alteryx)?

: If you received this file via email, ensure it was from a trusted sender.

: While usually a PDF, some specialized tax software may generate a .txt or data-ready file for electronic submission.