Knowledgebase
How to remove default elements from the category list table in Joomla
Categories added as menu items (Category List item type) display the articles in them in a table on your site's frontend. This table has default elements that you might want to remove: column names, author, etc. You can do this from the backend of your site.
To change the Category List options for the whole site (globally), go either to the Category Manager or to the Article Manager and click on the Options button in the upper right corner. In the window that opens click on the List Layouts tab. Then just mark the Hide buttons for the elements you want to remove. You can also set elements that are hidden by default to be shown on the frontend of your site. From the other tabs of the same window you can configure options for the articles, categories, parent categories (Categories tab), permissions and others.
To change the category list options only for a single menu item go to the Menu Manager (Menus>Menu Manager) and select the menu where the menu item is located. Then click on the name of the menu item itself to edit it. On the edit page click on List Layouts on the right side and from the drop-down menu for each element select whether you want to hide or show it, or just leave the default global settings.
For some more details and screenshots check out the tutorial on removing Joomla category list table elements.