$ sudo apt-get update
$ sudo apt-get install erlang-webtool 

erlang-webtool is installed in your system.

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

$ sudo dpkg-query -l | grep erlang-webtool *

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

erlang-webtool package basic information: