The EULA is a binding contract between the developer and the end user who purchases, downloads or installs a copy of the product. Since this is a contract, it is legally binding and you need the agreement of an end user. Perhaps the most important section of this legal document is the section that deals with how a user should use (or not use) your website and app. For example, if your website or mobile app collects or uses personal data from those who use it, you must have a legal statement informing users that you collect personal data, what personal data you collect, and how you use it. . . .