Note: This option requires the Spacing add-on in GP Premium.
You can adjust the padding inside your content container in Appearance > Customize > Layout > Container.
The value you see is in pixels, and controls the amount of space between the edge of your content container and content inside of it.
Note that this can be adjusted separately for desktop and mobile by using the toggle buttons.
Content Padding Not Working
If you have content paddings set in the customizer but it’s not working/showing no paddings at all, the reason is likely that the Content Container options are being applied through the Layout Metabox or a Layout Element.