Layout: Customizer > Layout > Sidebars > Blog Sidebar Layout/Single Post Sidebar Layout
Font: Depends what you are wanting to change, they should all inherit from the Customizer settings. Let me know if you want to change something specific. A link to your site might help.
Thank you, Leo. I have decided to keep the Sidebar.
About to customise the blog layout I have use Elementor. Anyway, I have problems to remove the Content Tittle. In Disable Elements I have checked the Content Title box. In each page. In Posts, Pages and Elementor > My Library > Blog Templates.