The phrase "develop them into" is correct and completely usable in written English.
You can use it when you want to express that you are transforming something into something else. For example, "We need to develop our ideas into actionable plans".
A skillful author can develop them into more complex individuals.
The aim is to develop them into world-class athletes.
Expectations are high to develop them into a novel class of anti-infective agents.
Only a few corporations recruit bright people, develop them into stars, and do everything possible to retain them.
A far better strategy is to take the people that they have and develop them into blended executives.
"We realized we had trained thousands of kids the basics but had nowhere to develop them into real golfers," said David Rivel, the foundation's executive director.
Although many improvements have been reported for in vitro culture of follicles at early stages aiming at developing them into competent mature follicles, these methods are still in development.
He often said his major contribution was finding dedicated young people and developing them into union organizers.
This is Tati taking his brilliant sight gags and routines for a spin before he developed them into the famous full-length movie that came two years later.
Although many of the psychoactive elements of the cannabis plant were discovered in the UK, he said, developing them into medications has been severely hampered by excessive regulation.
Through peer review, 20 of the best were selected, and trainees developed them into prototypes and tested them with customers during a three-month, part-time boot camp.
