Form 8594 must also be filed if the purchaser or seller is amending an original or a previously filed supplemental Form. 8594 because of an increase or decrease.Enter your name and taxpayer identification number (TIN) at the top of the form. Then check the box for Purchaser or Seller. Find the forms you need Choose Current year forms or Past year forms, and select By form number or By tax type. There are two easy ways for you to access our services still: - Complete an online request for services form on our website. Form 8594 is a tax document required in certain business sales where the buyer acquires assets rather than stock or equity.