How can I remove this?
Looks like you have incorrect syntax in your theme code, like maybe a missing closing javascript element (if you don’t have that then all that JavaScript code can be let loose and leek into the html).
I would revert to your previous theme version before the latest edits you / someone made. If you don’t a backup theme to revert to, start doing this: Every time you edit the theme, first duplicate the live theme, then work on the backup theme, and publish when it’s ready.
If you don’t have a backup, start with the theme.liquid file and read the code and include / render statements and follow those templates and double check the syntax. For example, if that is only happening on the home page, check theme.liquid and index.liquid. If it’s happening on every page, it’s likely in theme.liquid or header.liquid.
If you haven’t edited your theme in awhile, look at the apps you recently installed and contact them if you’re not sure if they added code to your site.