Hello,
You can change the layout or set the custom width of your pages from Theme Settings >> General Layout >> Set the Site width as boxed or custom as per your requirement.
If you want this custom width to apply only to single post pages without affecting other pages, we recommend using Theme Presets. This allows you to apply unique layout settings to specific post types: https://ibb.co/VhJ8YHp
Please refer to our documentation for guidance on using presets: https://xtemos.com/docs-topic/theme-settings-presets/
Best Regards,
.
