When more
tool options are available than there is room to show them, click these
buttons to reveal the additional options.After you select a tool from the Tools toolbar, set its options in the Tool Options palette. Options include such settings as brush size and shape for painting tools and line width for drawing tools. By default, the palette is underneath the standard toolbar. The palette displays options grouped into bands, which you can minimize and drag within the palette. To display a minimized band, click its handle or right-facing arrow.
Set the options before you use the tool. You cannot edit settings in the Tool Options palette for brush strokes or objects you have already created.
Although the items in the Tool Options palette depend upon the active tool, here are features common to all or some of the tools:
Presets Scripts that load specific settings for a tool. For more information, see Using and Creating Presets.
Arrow button When more
tool options are available than there is room to show them, click these
buttons to reveal the additional options.
Apply button 
Some tools
(Crop, for example) have this button. Click it to apply the changes you
have made or execute the action.
For information on moving, hiding, and displaying the Tool Options palette, see Using Palettes.