Step 1: Complete the taxpayer information section. Looking for experienced business sales lawyers in NYC?Contact us for skilled legal representation today! Identify the parties involved in the transaction. 2. The most important document in a business sale is the "purchase agreement" (also known as the "sales agreement" or "acquisition agreement"). Buyer can become taxable in the state where target business is and the state's apportionment formula may become applicable to the buyer's worldwide operations. The first step is to determine the value of the business or asset that you would like to purchase so that you do not overpay for it.