You can always view the documentation of the latest release at erlang.org/doc

If you want to view the documentation for older releases they are available through the download page for each release, for example, you can reach the Erlang/OTP 17 documentation on the Erlang/OTP 17 Download page.

Even older releases can be found in the Erlang documentation archive.

The documentation for each Erlang/OTP version can be downloaded from the release on github. For example, you can download the Erlang/OTP 23.3.4.10 documentation here.

If you want to build the documentation locally you need to follow the following steps

The environment should be set up in the usual way for building Erlang/OTP. Set the ERL_TOP environment variable:

cd <your-otp-build-directory>
export ERL_TOP=`pwd`

Build in the usual way as described in the README file. Briefly:

./configure
make

If you are building for release into your own local directory, you’ll need to issue the configure command as follows:

./configure --prefix=<localdir>

To build the complete documentation for all applications, build it from the top:

make release_docs

If you want to build the documentation only for a specific application, you must build erl_docgen first. Enter the erl_docgen directory and generate the necessary files:

cd $ERL_TOP/lib/erl_docgen
make release_docs

Then enter the directory for the specific application directory, and build its documentation:

cd $ERL_TOP/lib/<application>
make release_docs

This will generate the application’s documentation in three formats: UNIX-style man-page format, HTML, and PDF for the corresponding chapter in the Erlang/OTP Reference manual.

The HTML documentation can be viewed by opening index.html in your browser:

cd $ERL_TOP/release/`$ERL_TOP/erts/autoconf/config.guess`/doc/