By default in Ubuntu 16.04 (and above) files and folders are displayed as a grid of icons.
The following steps show how to change this so files and folders are shown as a list.
- Press Ctrl + Alt + T on your keyboard to open the terminal
- Run the following command
gsettings set org.gnome.nautilus.preferences default-folder-viewer 'list-view'
- Files and folder will now be shown in list view by default