How do I delete all of the emails in my iCloud emails app on a desktop computer?

I do not use the Apple email app on my iPhone 11 because I have very little storage space and I do not want storage to take up too much on my smartphone and in iCloud. I always log into my Apple Mail via a Windows desktop computer in the Google Chrome web browser. I had searched for easy-to-understand methods, but I couldn't understand any of them.