If you're looking to direct your customers to the newsletter sign-up box on your e-commerce site by, for example, creating a link to add to a social media post, you can use the technique below to do so.

The newsletter sign-up box on your website has an anchor/ID tag attached to it, which means it can be pointed to in a URL.  To find this anchor/ID tag, using the Chrome browser, right-click on the Signup box on your site, and then click Inspect:

This will open a pane on the right-hand side of your browser page, and you'll see a portion of the code which makes up the page.  The specific section you need will have been highlighted, as that is the area of the page on which you right-clicked to inspect:

Within that highlighted section, the information you need is the ID, as indicated in the screenshot below:

You can now use the ID you see there to create the URL by adding /# and the ID to the end of the page on which the newsletter sign-up box appears.  Using the ID from our example above, for the sign-up box on your homepage, this would be:

https://www.yourdomainname.co.uk/#footerEmail

The same can be done for other pages where the sign-up box appears too, e.g.

https://www.yourdomainname.co.uk/pages/contact/#footerEmail

You can now use this URL to send your customers directly to a newsletter sign-up box on your e-commerce site.