Use the ZOOM tool on the toolbar to make your text appear either smaller or larger to suit your preferences.

The formula bar (below the other toolnbars) displays the contents of the active cell.  All formulas begin with an equals sign.  Remember, you cannot change cells until you complete a formula either by clicking on the "X" button (to cancel it), the TICK button (to accept it), or by hitting the ENTER KEY (also accepts it).