Many platforms are emerging recently and businesses need to work with all of them, therefore, creating applications that work on multiplatform like Android, IOS, Windows …etc. is necessary these days.Building a separate native application for each platform as well as working separately with both Frontend and Backend is costly in several respects, including time, effort and cost.using Cross-platform tools and frameworks is the best solution to the problem of multiple platforms and the need to deal with all of them. This paper discusses the most famous, modern, and widely used Cross-platform tools to introduce the best way to build an E-learning application that works natively in multiplatform using only one programming language, and even it doesn’t require work with the Backend side. Finally, we have created a sample E-learning application using Flutter with Firebase as a Backend. Due to the Corona pandemic, e-learning has become a mandatory requirement as a primary or secondary method of education, this application work on all platforms (Mobile and Desktop), and we tested it on Android and Web Browsers.