Can not find where the index.html file is.
Thank you for your question!
WordPress websites use .php template files to manage page content, and you can paste tags into the <head> section by editing the header.php file contained in your theme files.
Adding code to the header.php file is one way to get those tags working on your website, but there are some reasons to use a different solution to make those modifications. The biggest one is that any future theme updates will overwrite your customizations when applied and force you to add the code all over again.
You can avoid having to redo your work after every update by using a plugin to manage those code changes and this is one of the most popular options available in the WordPress repository.
I hope that this information helps you make the changes you need and please let us know if there is anything else that we can do for you!
Customer support service by UserEcho