Some of the Builder templates allow you to adjust the width of the content area of the website. The site width minimum and maximum will change depending on the template you have saved. In the below example, the Madison Avenue template is saved.
To access this setting, first click on the Builder icon then hover over settings and click on general.
The first option you'll see is site width. Enter a number then click on save changes.
Below is an example of what your page could look like on a laptop screen at 900 pixels:
Below is an example of what your page could look like on a laptop screen at 1200 pixels:
Note: The page in the examples above is an Info page using the "Stackable Left" layout.