First, login to your site admin, go to the backend of the store, click on ‘Online Store > Themes’ in the left menu and then ‘Customize’ on the right, then on the bottom left side of the screen click where it says “Theme actions”, go to “Edit code”. Under the “Layout” folder, click on “{/} theme.liquid” and this will show the main structure for your site.
Scroll down to the bottom, your Javascript code should typically go right before the </body> tag, so once it has been pasted in just hit “Save” and the insurance badge should pop up when you view your site from the front end.