You do not need an 8om account to make a QR code. Open the QR tool, paste a URL or type text, and download the image. That is the whole first visit.
Pick a destination that can change
If the poster will live for months, point the QR at a short link, not a long campaign URL. When the offer changes, you update the link — not the print.
Keep the code readable
High contrast, quiet margin, and a size people can scan from the distance they will stand. A tiny code on a glossy table tent fails more often than a plain black-and-white square.
Test before you print
Scan from a second phone, in the lighting of the real room. If it fails, enlarge it. Do not add a logo that covers the finder squares.
When you later want history, NFC, or a site behind the scan, Start Free and keep the same 8om workspace. The public tool stays free to try.