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Enter Google Tag Manager ID (Container ID) to enable. When enabled the GTM container JavaScript snippet will run on every page of a website.
Log in to your Google Tag Manager account and open a container. In the top right corner (next to the Submit and Preview buttons) you’ll see some short text that starts with GTM- and then contains some letters/numbers. That’s your Google Tag Manager ID. The same ID can be found in the Google Tag Manager container’s code snippet.