An APA spells out the conditions and terms under which a seller will transfer all of the assets that belong to the business to a buyer. Form of Asset Purchase Agreement.Attached as Exhibit. An asset purchase agreement is a legal document used when buying or selling a small business. Read on to understand the basics. A sales agreement for buying a business is necessary for keeping both the parties on the same page and avoiding any legal trouble. 1.2 Agreement to Purchase. The Office of the City Register records and maintains New York City real property and certain personal property transfer records, such as mortgage documents.