The difference is where the destination lives. A static QR code contains the final destination. A dynamic QR code usually points to a hosted redirect that sends the visitor somewhere else.
Static QR codes are independent
Once created, a static QR code does not need a QR platform to keep working. It will continue to open the encoded destination as long as that destination remains available.
The tradeoff is that the address cannot be changed after printing. To use a different destination, you need a new QR code.
Dynamic QR codes are editable
A dynamic code normally contains a short hosted link. The platform can change where that link redirects, which is useful for campaigns and printed materials that need ongoing updates.
That flexibility also creates a dependency: the redirect service and account must remain active for the printed code to work as intended.
Which should you choose?
Choose static when the destination is final and independence matters. Choose dynamic when changing the destination after printing is worth relying on a hosted service.