"was formed into" is correct and usable in written English
You can use it when you want to express a transformation or transition from one thing to another. For example, "The team of consultants was formed into a new department."
The eastern end of the park was formed into the Horse Guards Parade in the 18th century.
The meat was formed into a long sausage shape, served atop a hillock of chelo crested with a saffron-yellow stripe.
In that year the fleet was formed into three squadrons with the admiral commanding the centre squadron, his ships flying red ensigns.
The neck, formerly set into a wood block, was formed into a brace, or shoe, that projected a short distance inside the body and was glued to the back; this gave extra stability against the pull of the strings.
When British Togo was attached to the Gold Coast, French Togo was formed into a distinct unit until 1934, when a kind of economic union was established with Dahomey; this was replaced in 1936 by a qualified integration with French West Africa that lasted 10 years.
The Romans conquered southeastern Gaul in the years following 125 bc, In 121 bc the coast from what is now Montpellier to the Pyrenees with its port of Narbo Martius (modern Narbonne) and its trade route by Tolosa (Toulouse) to the Atlantic was annexed by Rome, and in 118 the city of Narbo itself was formed into a Roman colony and made the province's capital.
The rubies, said Mr. Frawley, were formed into the rock.
These bits are formed into an encoded data stream.
Football writers will be formed into a pool to write for all three titles.
Pancetta, beans, tomatoes and polenta were formed into a cake and fried.
Students are formed into multidisciplinary and multicultural teams and given real projects to work on.
