You can find Content Spacing settings under Appearance Customize Spacing Content

 

Container Spacing

You can set spacing for main container and primary container. Know more about the container here.

Main Container Padding

Space Inside Main Container will be applied as a padding to the container. It will allow you to manage space between page/post content and the container edges.

Main Container Margin

Space Outside Container values will be applied as a margin to the container.
Top space value will allow you to manage space between header and container’s top edge. While bottom space value will allow you to manage space between footer and container bottom edge.

Primary Content Area Padding

Space Inside Primary Container will be applied as a padding to the primary container. It will allow you to manage space between page/post content and primary container edges.

Primary Content Area Margin

Here you can set top and bottom margin for primary content area.

 

Heading Spacing

Here you can set margin for heading tags (H1 – H6) used in primary content area.