Google Tag Manager setups can turn complex pretty quickly. Without proper documentation, you'll end up spending hours to understand what is what or where to find/change a particular aspect of the container.

That is why upon completion, GTM Expert always provides you a filled-out documentation file in Google Sheets that includes:

1. Summary of the edits

2. Every single change, explained

3. Comments & remarks

So whenever you or someone else wants to make an edit or verify something quickly, this document can provide the basis.