With over 6.3 billion global smartphone users, building an accessible app is crucial to include everyone, regardless of their condition or situation. Mobile app accessibility involves designing and developing apps for people to understand, interact, and navigate regardless of their disability, race, gender, or age. The standard for ensuring mobile app accessibility is based on the internationally recognized Web Content Accessibility Guidelines, version 2.0 (WCAG), Level AA. Developing an accessible app is essential as it provides universal access to users, is morally right, legally required, and good business sense. Best practices include providing proper labels, keeping gestures simple, and ensuring color contrast meets the minimum of 4.5:1. Mobile app accessibility testing involves assessing design elements and controls to determine their accessibility. Automated tests can help discover many accessibility flaws throughout the development process, but it's best to combine automated and manual testing. Developing an accessible app should be viewed as an essential part of the app development workflow rather than an add-on feature.