Before you buy an existing business, find out if the business owes any Texas taxes. An asset purchase agreement (APA) is a written legal document that formalizes purchasing a business or substantial commercial asset.An asset purchase agreement is the legal document that will govern the transfer of ownership of a business's assets from the seller to the buyer. In an asset sale, the new owner purchases the business's physical assets. The seller retains all rights to the legal entity. Both the seller and purchaser of a group of assets that makes up a trade or business must use Form 8594 to report such a sale. Fill in the business start date, sales tax permit number, and check any boxes that apply. If sold, please fill in the New Owners name. Before an offering or sale of a business opportunity in. Texas, the principal seller must register the business opportunity with the secretary of state. Tex.