You can change the way pages are displayed, by selecting options in the View menu.

Normal Mode

Displays artwork in a standard window with visible grids and guides, non-printing objects showing, and a pasteboard color as selected in the user preferences.

Preview Mode

Displays artwork as if it were output, with all non-printing elements suppressed (grids, guides, non-printing objects), and a pasteboard color as selected in the user preferences.

Tracking Mode

Displays artwork in a symbolic view, filled with workspace color and with labels depicting names and status (configurable).

Sample Mode

Displays sample text and images instead of holes, or real text/images.