Smart phones have become part and parcel of the modern lifestyle. In addition to offering usual contacting service, these devices offer a wide variety of mobile applications ranging from games to money transfer and from home automation to fitness and chronic disease management. m-Health is the concept emerged with the development and usage of mobile applications dedicated for healthcare. Such apps offer a unique opportunity for users to have control over their own health through lifestyle, diet and medication management. Moreover, the users also get a chance to remotely connect to their doctors and community for timely advise and intervention, reducing their risk levels. Thus, m-Health could largely contribute to SDG 3, as it offers a broader access to healthcare for communities who might lack conventional healthcare facilities. This chapter opens with a brief discussion on history and evolution of mobile apps, then describes most commonly available and accessible categories of mobile apps developed for a wide variety of applications including fitness tracking, remote health monitoring, epidemic tracking, and mental health monitoring. The major technologies supporting m-health and discussed along with the challenges and barriers causing hinderances for widescale adoption of m-health, and finally, future opportunities are presented.