i want four formal letter for my english exam.

Follow the mentioned link for references related to formal letters:

https://www.meritnation.com/ask-answer/question/1-you-are-ridhima-write-a-letter-to-the-editor-of-a-newspa/english/2913840

https://www.meritnation.com/ask-answer/question/you-are-rohan-during-a-visit-to-mumbai-you-happened-to-visi/english/2868422

https://www.meritnation.com/ask-answer/question/write-aletter-to-the-editor-of-the-local-newspaper-telling-h/english/2775940

https://www.meritnation.com/discuss/question/2373317