Why do people in the Middle East use English letters to write on the internet?

My computer is from the US so Idk why they would have arabic letters on it. Also, it's very very hard for me b/c I don't know how to spell or write words in arabic that well tbh, and I can't read that well either. It makes it easier for me so ya. Im learning though so inshallah I will be able to read the quaran in arabic instead of using the english one.