1.QR code - This is the original version of the QR code created by Denso Wave in the 1990s. It's easy to identify by its three finder patterns in the bottom–left, top–left, and top–right corners.
2. Aztec code - While it looks similar to a QR code, the Aztec code, developed by Welch Allyn, contains only one finder pattern, right in the middle.
3. Maxi code - This type of QR code is used by the United States postal service. It's similar to the Aztec code in that it places the finder pattern in the middle, but it uses a honeycomb pattern instead of squares.
4. PDF417 - It looks like a mix between a QR code and a barcode and is easily recognizable by its rectangular shape.
5.Semacode - Developed by a software company of the same name, the Semacode is a data matrix that looks a lot like an ordinary QR code but doesn’t have recognizable finder patterns.
