Final answer:
The command option for drawing rectangles with rounded corners is often the 'Rounded Rectangle Tool', which is available in graphic design software such as Adobe Photoshop, and the radius value can be adjusted to control the curvature of the corners.
Step-by-step explanation:
The command option used to draw rectangles with rounded corners in many graphic design software programs is often referred to as the Rounded Rectangle Tool. In some applications like Adobe Photoshop, you can select the Rectangle Tool and then choose the option for rounded corners in the options bar at the top. Adjusting the radius value associated with this tool will allow you to control how rounded the corners of the rectangle will be. As you draw the rectangle on your canvas, the corners will automatically be rounded according to the radius setting you've chosen. This tool is very useful in graphic design and UI/UX design to create buttons, frames, and other elements with a more aesthetic and softer appearance as opposed to sharp, right-angled corners.