Want to delete a suspicious meta tag

there is an suspicious meta tag in my website, which is added by an unknown email ID. How can I delete it?

Where are you viewing this meta tag as you can just try deleting it from various places, all of which are manual entries by the Wix Editor.
https://support.wix.com/en/article/adding-custom-meta-tags-to-your-site
https://support.wix.com/en/article/header-code-meta-tag-guidelines
https://support.wix.com/en/article/adding-seo-page-titles-and-descriptions-meta-tags
https://support.wix.com/en/article/adding-keywords-as-meta-tags-to-your-pages
https://support.wix.com/en/article/verifying-your-site-using-header-codes

If you can’t delete the meta tag yourself, then I would go through Wix Support and ask them directly.
https://support.wix.com/en/article/contacting-wix-support

Thank You for this useful information