The full source code of Tezos is available on gitlab.com/tezos. Tezos is written in OCaml, an industrial-strength programming language supporting functional, imperative and object-oriented styles . OCaml is a functional programming language that offers speed, unambiguous syntax and semantics, and formal proofs of correctness.
The simplest way to contribute to Tezos is to report an issue (as described in the previous chapter). However, if you are proficient in OCaml, you can correct the error yourself or add new features and submit a merge request to the admins of the Tezos repository.
For more detailed information about how to proceed, please refer to the official contribution guidelines here.