How to correctly anonymize IP for Tag Manager code?

Question

In Google Tag Manager we get this code for placing on pages

<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-ADSAFASDF');</script>

Here we can find the code we should use for anonymizing IP https://developers.google.com/analytics/devguides/collection/gtagjs/ip-anonymization

 gtag('config', '<GA_TRACKING_ID>', { 'anonymize_ip': true });

Where should I place it? If I place it right after the code (before ending /script tag or inside separate script) using Tag Assistant Chrome extension I can see the error

Invalid call to gtag(), the Global site snippet is not installed

How to properly insert the code and where?

Answer 1

Google Tag Manager doesn't process or store IPs. It is the Google Analytics tag inside of Google Tag Manager that you need to configure to anonymize IPs.

Go to GTM & edit your Google Analytics Tag(s) or Google Analytics Settings Variable:

1. Go to More Settings > Fields to Set
2. Add a new field. Configure the field with:
   1. Field name: anonymizeIp
   2. Field value: true