Under view » Info Layer ribbon the Info Layer options can be set while they have to be activated either through start » Info Layer or the option with the same name under the dropdown in the quick menu in the top left corner of the display.
You can choose to let either the netname, size of the elements or a freetext be displayed (freetexts are often used in combination with a plugin, e.g. a plugin that only displays the name for testpoints). Usually only the topmost active layer is labelled, but if you activate "All Layers" all visible layers are labelled even though this option might get unclear with increasing layer count. Furthermore, you may limit the labelling to one or more specific object types like surfaces, lines, pads, or SMDs.