In this video, I'm going to show you how you can pre-fill an email address in a form field using tag manager. This is useful so that users don't have to type in their email address again. To do this, we need to identify the form field in the HTML code. We first right-click on the form field and select "inspect" to view the HTML code. We can see that the form field has an ID that uniquely identifies it on the page. Next, we can use JavaScript to access and fill the form field. We open the JavaScript console and type in the command "document.getElementById('id of form field').value". This selects the form field and shows that it is currently empty. We then use the assignment operator "=" to set the value of the form field to the desired email address, such as "test@test.com". This makes the form field fill with the email address. Alternatively, we can use tag manager to execute this JavaScript command. We create a new on-site tag in tag manager and choose custom HTML. We then wrap the JavaScript code in script tags and paste it into the tag. To ensure best practice, we wrap the code in a self-executing anonymous function. We also need to define a trigger for the tag to only fire on the contact page. We set it to trigger on the page view event when the page URL contains the word "contact". Once the tag is created, we can preview and debug it. We reload the page and see that the email address is now pre-filled in the form field. If we want to pass the email address to tag manager from our system, we can use the data layer. We can push the email address to the data layer if...