C is a general purpose language, used for a wide range of applications, from embedded computers to high-performance computing clusters.
C is commonly found in low level applications as it's a good alternative to harder-to-read assembly languages. It can be compiled to assembly to keep the same level of performance, while increasing readability, and providing a small level of safety with static types!
C was created by Dennis Ritchie at Bell Labs, and used to re-implement the Unix operating system. Now, it's one of the most used programming languages, with many compilers providing support for most available hardware and platforms - there are plenty of resources and support available to help you get started!