Fold Mountains are created through a process called orogeny. An orogenic event takes millions of years to create a fold mountain.  

• When a tectonic plate gets pressure from two sides, it gets folded. Some of its portion becomes elevated and forms the mountains. 
• The depressions form the valleys. The Himalayas, the Rockies, the Andes and the Alps are examples of Fold Mountain.  
• They are the young mountains of the world and hence they have some of the highest peaks of the world. 

Source: ICSE – Total Geography Class – IX