In 2019, Yves Benchimol, an engineer at the time, had an idea to help people put down their phones and start moving.

"I [thought] one of the main issues for people like me, and also the younger generation, is the time spent behind [our] screens," and being sedentary, Benchimol says.

He launched WeWard, an app that gamifies walking and offers a financial incentive to get your daily steps in: "Every smartphone counts your steps now so why not build a product that will help you to improve this number?"

Research shows that for every 2,000 steps you take, risk of heart disease, cancer and premature death decreases by 10%. Aiming for up to 10,000 steps a day is key to health and longevity.

Today, the French company has 20 million active users and has expanded beyond Europe to the U.S., Canada, Japan and more.

"Thanks to Apple Health and Google Fit, we have access to the average number of steps people [walked] before downloading the app. And we are trying to increase this number," Benchimol says.

"On average people walk 25% more, thanks to Weward."

Users earn hundreds of dollars a year on WeWard

WeWard users earn digital points called "wards" by walking, even if their phone is in their pockets while doing it as long as WeWard is connected to their go-to fitness app. This allows users to enjoy a screen-free walk and still rack up points. Wards can be converted into cash, gift cards, coupons and donations to charities.

"On average, people can earn a few hundred bucks per year. But it varies a lot because, of course, it depends on your physical activity first, but also the frequency of your steps," Benchimol says. Walking 10,000 steps every day will help you earn more wards than walking the same amount of steps every two days.

To date, the company reports that its given out over $20 million in cash to users of the app and $1 million in charitable donations.

"Top users can earn $1,000 per year," by completing challenges and buying products through the app's partners, Benchimol says. "For example, we are partnering with Nike. If you buy Nike shoes using the app, you will earn some wards."

The company realized that "some people are much more motivated by just helping others," and have recently partnered with Feeding America.

Users can compete with friends and develop a community of walkers in the neighborhood who also track their steps on WeWard. And in an effort to get people even more engaged, the app offers treasure-hunt like challenges. "Pokemon Go is one of our inspirations," Benchimol says.

Similar to the popular gaming app, WeWard encourages users to walk to specific destinations to collect cards that earn them extra wards.

WeWard positions most cards less than 500 meters away, or approximately 1,640 feet, from where a user lives so that they can collect them in five minutes or less. The team responsible for the app's functionality also ensure cards are accessible by not putting them in houses or restricted areas.

"We try to put cards where most people like to walk," he says. "You will find cards in front of museums, monuments [and] parks. In New York, you have a beautiful area in Central Park where you can find them."

The app's goal is to get people to walk more. For beginners, this could mean walking a few times a week. Users are challenged to walk every day or to walk further than they typically do to earn more wards.

The challenges offered in the app include walking 5,000 steps a day or walking 100 steps between noon and 2 p.m. — they each help you earn more wards.

The level of difficulty for each challenge depends on the user, Benchimol says. "We are trying to make it not too difficult, but also personalizing [it] to be adapted to your physical activity," he says.

"We have the very simple vision to make as [many] people as possible walk more."

Want to make extra money outside of your day job? Sign up for CNBC's online course How to Earn Passive Income Online to learn about common passive income streams, tips to get started and real-life success stories.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life.