How to find the GTM container ID
GTM allows you to set up different groups of tags by using containers. That's helpful if you manage multiple sites, or want to use different tags. Each container has a unique ID. You can find your container ID, formatted as "GTM-XXXXXX".
Go to your GTM home page. You can find your container name under the title of Container Name, and your container ID for the relevant container name under Container ID.