Many websites host their content on U.S serves, this has an effect on the performance on people who visit these websites from outside the U.S, mainly because international visits will take longer to load which will lead to low website performance. If you are aiming for international visits you need CDN since it is a tool that distributes copies of your static content to different endpoints in different countries which will improve your load times for all your visitors all over the world. Tools that will help and are easy to use are Cloudflare and Max CDN. Make sure to consult this guide to perform this hack.