Block Based programming is a simple programming language where developers (primarily beginners and young people) drag blocks into place in order to write their code. Code.org has reached millions of students by starting off with basic block programming. https://code.org/
Scratch is a programming language developed by The Lifelong Kindergarten group of Media Lab of MIT, which was headed by Mitchel Resnick, and Playful Invention Company, in Montreal. The simple interface and block based coding makes it easy for the most inexperienced user to dive into coding.