Hello, Sorrex,
Thank you for reaching out to us.
Some hosting providers offer regular backup services for their customers, which can be invaluable for maintaining the integrity of your website’s data. We recommend contacting your hosting provider and requesting them to restore a backup of your site.
At this time, we do not have sufficient information to determine what actions may have caused the issue. We suggest reviewing who else has access to your website, as they may have inadvertently removed the header and footer content.
Best regards,
8Theme’s Team