Log in to the Shopify administration interface. In the left menu, click on “Online Store” and select “Themes” from the drop-down menu. On this tab, click on “Customize” in the preview of your page.
You will see the page editor. In the left panel, click on “Theme Actions” at the bottom and select “Edit code” from the drop-down menu. A new tab with the exploratory files.
In the “Layouts” file, open the layout you use on your pages. This opens the text editor for the code. Insert the HTML code of your package into it - it must be inserted before the tag
</body>. Then save the edits.