A Share Purchase Agreement (SPA) is a legal document used when one person or company agrees to buy shares from another person or company. This agreement clearly mentions how many shares are being sold, at what price, and on what terms. It also includes details like responsibilities of both the buyer and seller, the date of the transfer, and any conditions that must be met before the deal is completed. SPAs help avoid disputes by making everything clear in writing. It is an important document in mergers, acquisitions, or when transferring ownership of a business.