Could anyone assist me please? Generating a safe, temporary QR code to a PDF?

[usonian]

2. Quick web search

In general, to protect your systems, definitely upload the pdf to some off-site storage.
If you use any "cloud storage" such as Google, dropbox, box, who knows what, perhaps there's an option to share files via a QR code.

One example I found:
If your file is on Google Drive,
https://workspace.google.com/marketplace/app/qr_code_file_sharing_for_drive/878471720006

Overview
You can share your Google Drive™ file or folder via QR Code easily. You can share with readable or writable permission. Moreover, you can unlink sharing anytime. After generating QR Code, you send this QR Code to your friends, colleagues or partner. They can use their mobile devices to scan QR Code and access Google Drive™ file or folder directly. If they installed Google Drive™ application, add on will redirect them to file directly inside Google Drive™ application or web browser

Says free of charge trial (I don't know the limits)

Others were odd. (like a short time limit)

If you upload your pdf somewhere and only have the link, there are QR code generators that will convert the link into a QR code.