This is somewhat of an interesting question. It is possible to make a strong argument that technology can't be good or evil. Technology is a tool. It is not a living organism subject to social and moral norms; therefore, applying morality to it does not make sense.
This question is probably aiming to ask how technology can be beneficial if the assumption that something beneficial is "good." The answer to that is subjective. One person might think that the development and usage of smartphones is hugely beneficial, because the devices allow people to communicate with other people in a wide variety of ways (text, call, email, social media, etc.) and in almost any location. This gives people the ability to conduct business at all times of day and locations rather than being tied to the office. The devices are also multi-application. They can be entertaining. They double as cameras, so people don't have to carry around multiple devices. They are music storage units. All of those usages could be very good and beneficial.
On the other hand, that particular piece of technology can be a distraction. Plenty of car accidents happen because people are texting or talking while driving. This is why many cities and states have laws about cell phones and driving. The devices have made cheating in schools much easier, and plenty of photos have been taken and published without the person's permission using cellphone cameras.
Technology, like any other tool, is good and bad depending on how the user uses the technology.