A dynamic QR is a QR code created afresh for each payment. It contains the merchant's payment details together with the exact amount and a unique transaction reference, and often an expiry time. The customer scans it with a banking or wallet app, sees the amount already filled in, and approves. The code is shown on a terminal or till screen, on a printed bill or on a web checkout page.
It contrasts with a static QR, a fixed code, usually printed, that identifies only the merchant and leaves the customer to type in the amount. Because each dynamic code maps to one order, the merchant's system can match the incoming payment automatically and show confirmation at once, and the customer cannot enter the wrong amount. A single-use code is also harder to tamper with than a printed sticker. Dynamic codes are standard for larger retailers and online merchants on QR payment schemes such as Pix and UPI.