Our store uses WooCommerce (WordPress) and we use Google Analytics to track our transactions. Because users leave our site to make their payment via Authorize.net, Google Analytics is unable to correctly attribute the subsequent conversions (showing as referrals from authorize.net).
We've setup Analytics in Tag Manager and have enabled third party cookies (auto link domains), but without actually adding the code to the authorize.net pages, this is useless. I've seen many places where your customers ask this exact question and yet I've not seen a single workable response. Please create a way customers (or their developers) can enable and implement this tracking continuity.