Obviously I’m not the GM here, but if I were a dystopian corporate dictator or their chief of identity services, I would have the wrist tattoo ID tag be a QR code with additional details like name and date of birth printed in plain text next to it so that it can both be scanned for a full profile and the basic details be taken down in a hurry when there isn’t a scanning tool on hand or there isn’t time to get it out and use it. Barcodes are a trope that is often used but I dunno if a tattoo in human skin could get the resolution needed to reliably define the fine bars for scanning. A QR code is composed of blocks, and so doesn’t need the same level of resolution. I also wouldn’t simply use a string of numbers like the Nazis did, because this isn’t a setting where the ID tag is on a person completely under your power - in this setting, people live on the fringes and are likely to resist if they see fit, rather than all of them being contained in a concentration camp. Numbers don’t give you the same info in the same timeframe, you need more. These tattoos will also need to be touched up over the lives of the subjects being monitored - and for monitoring purposes I’d also have an RFID tag implanted underneath the QR code which could report tampering, and potentially permit tracking. Only issue there is that RFID tags respond rather than broadcast, but that just means they don’t need power. They could also be used to unlock doors and cars and stuff so that they have utility and people don’t overthink their purpose.