You should make your EULA available at any time to people who want to review it.
Add a link to your EULA to your business website's footer, and in your app store listing. This allows potential users to check it out before buying or downloading your product.
Include a link to it somewhere within your app, such as in a "Legal" or "About" menu. Also include your EULA at the beginning of the installation process and ask for users to consent or agree to it.