Elixir creates an AST which is transformed into Erlang Abstract Format (http://erlang.org/doc/apps/erts/absform.html) which is then compiled into Erlang bytecode by Erlang compiler.

Erlang VM's bytecode is largely undocumented (except for third-party attempts like http://erlangonxen.org/more/beam and http://beam-wisdoms.clau.se/en/latest/). So all languages on the Erlang VM either create and compile Erlang Abstract Format or transpile to Core Erlang (https://8thlight.com/blog/kofi-gumbs/2017/05/02/core-erlang....)