$ sudo apt-get update
$ sudo apt-get install erlang-erl-docgen 

erlang-erl-docgen is installed in your system.

Make ensure the erlang-erl-docgen package were installed using the commands given below,

$ sudo dpkg-query -l | grep erlang-erl-docgen *

You will get with erlang-erl-docgen package name, version, architecture and description in a table

erlang-erl-docgen package basic information: