1.Would you please distingiuse the two words and how they differ?
2.Where we may use?
3.Notify the prepositons we can use with them and suggest how come?
It's 'in spite', two words, and despite. They both mean the same and are essentially interchangeable. 'In spite' is used with 'of' and 'despite' is used alone. "In spite of the weather..." "Despite the weather..."