The options bar appears below the menu bar at the top of the workspace. The options bar is context sensitive—it changes as you select different tools. Some settings in the options bar (such as painting modes and opacity) are common to several tools, and some are specific to one tool.
You can move the options bar in the workspace by using the gripper bar, and you can dock it at the top or bottom of the screen. Tool tips appear when you position the pointer over a tool. To show or hide the options bar, choose Window > Options.
To return tools to their default settings, right-click (Windows) or Control-click (Mac OS) the tool icon in the options bar, and then choose Reset Tool or Reset All Tools from the context menu.
For more information on setting options for a specific tool, search for the tool’s name in Photoshop Help.