Dimension - Width
Width settings are located under Dimensions. As the name suggests, it allows you to adjust the width of a component. You can also fix the maximum width of a component.
Remember, once you fix the maximum width of a component, it will not adjust its width according to the screen size responsively.
Adjusting the Width of a Component
As you click on the component whose width you want to adjust, the Style Manager of that component opens automatically in the Right Toolbar. You only have to go to the category, "Dimension" and adjust the width of the component as per you layout design.
Pixels, Percentage, Viewport, EM & REM
You can also assign the size in fixed pixels, % of screensize, viewport width, em and rem.