write a letter to your father requesting him to send you some money so as to enable you to go on a picnic

The sample letter given at the link below will help you to frame your answer.

https://www.meritnation.com/ask-answer/question/you-are-rahul-living-in-the-hostel-of-st-l-lucknowyou-need/letter-writing/4573552

We recommend that you frame the answer on your own and revert to us for feedback. We will be happy to help you suitably.