You cannot add the google ad code though admin panel.
So you need to find the <head></head> in it’s original codes.
And here is how you can located the intended file:
/core/resources/views/templates/basic/layouts/app.blade.php
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title> {{ $general->siteName(__($pageTitle)) }}</title>
@include('partials.seo')
<link href="{{ asset('assets/global/css/bootstrap.min.css') }}" rel="stylesheet">
<link href="{{ asset('assets/global/css/all.min.css') }}" rel="stylesheet">
<link rel="stylesheet" href="{{ asset('assets/global/css/line-awesome.min.css') }}" />
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/slick.css') }}" />
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/magnific-popup.css') }}" />
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/simplebar.min.css') }}" />
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/main.css') }}">
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/custom.css') }}">
@stack('style-lib')
@stack('style')
<link rel="stylesheet" href="{{ asset($activeTemplateTrue . 'css/color.php') }}?color={{ $general->base_color }}">
</head>
```
Just added whatever Js you need to put into the header.
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