For a shop, marking shows up mostly at the checkout: when selling a marked product the cashier must scan the DataMatrix code, not the ordinary barcode. The code goes onto the receipt and the item is recorded as sold in the system.
That requires a 2D scanner that reads DataMatrix quickly and reliably (the code is often small, on curved or glossy packaging), POS software that supports marking, and cashiers trained to find the code. It also helps to check codes when receiving goods.
Older 1D scanners cannot read DataMatrix, so preparing for marking often starts with replacing scanners. BDB will recommend a suitable 2D scanner for your till.