Google tag id is the id that you need to start tracking remarketing events and conversions. The format is usually like AW-12345678, however, it could also be GT-XXXXXX. I recommend using the one that starts with AW. Follow the steps below to find your Google tag id for Google Ads.
1. Log in to your Google Ads account.
2. In the left menu, click on Tools and then select Data Manager. Your Google Tag can be found under the Google Tag title. To manage it, click Manage on the right side.
3. You will see the summary of your Google tag information under Your Google tag title. Click Installation instructions. 
4. Select Install manually tab. There you can see the full code to add to your website. We will only need the id so select either one of the ids, right click and copy it. 
