The appearance of the sidebar below the content in your WordPress site
Ideally, the sidebar is supposed to appear beside the content. This error is frequently caused by broken HTML code. When you are editing WordPress theme and you forget to close an HTML div tag, it may result in the sidebar appearing below the content area.
Another possible cause of the sidebar appearance below the content is an error in your theme CSS code, particularly when the CSS with is not set appropriately or the clearing float rule that is applied to the content area and the sidebar.