Hello @MarketerL8979 ,
When emails are sent out, a unique URL is generated for each one, so there wouldn't be a default way to do what you're describing in your account. One thing you could do, especially if you have the archive widget available via a Plus plan or addon-subscription, is to make a QR code that links to a webpage where you host your newsletters. That way, even if you change the newsletter(s) featured on that page, the webpage's URL stays the same and thus the QR code remains the same as well. This can also apply if you choose to have a public / limited access drive folder where you host the PDF / image versions of emails.
Essentially, as long as you have a singular webpage (URL) dedicated to hosting the various links, PDFs, or however you choose to host the emails on it, then you can have your singular QR code remain unchanging through all the edits to that page.
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