There is a setting called "Enable Article Select Copy" that you can find under Tools > Manage Settings > Miscellaneous tab page of the admin area as shown in the image below. Just turn ON that setting and you would be able to select and copy text on article page in the Public area.
Article ID: 61
Created: January 22, 2015
Last Updated: September 10, 2020
Author: Ajay Chadha [support@phpkb.com]
Online URL: https://www.phpkb.com/kb/article/how-to-enable-text-selection-and-copying-on-article-page-61.html