If I understand your question correctly, you are wanting some ideas about why it is necessary to learn English. Here are some thoughts on that:
English is fast becoming a "universal language." It is used in business across the globe; it's used in entertainment, sports, and politics. People who live in non-English-speaking countries will have a definite career advantage if they become fluent in English, and will also have the opportunity to communicate with more people from other countries who also speak English. Learning English opens the door to a wider world.
I hope this helps give you some ideas for your essay!