Web Manager

Installed from distro

Running FreePBX and the http webmanager is not enabled.

manager show settings
Web Manager (AMI/HTTP): No

Therefore no /etc/asterisk/http.conf exists.

How do I enable the webmanager via the FreePBX interface?

FreePBX is a web-based manager for Asterisk. If you want to use the built-in web server for Asterisk, I would suggest not starting with a FreePBX distribution.