It is not a licence, but a card. Instead of having all the tacho info recorded on a paper disc (analogue tacho), new vehicles for last 2 years must have digital tachos fitted. To use this, you need a digital tacho drivers card. Looks like a driving licence card, but has a chip on it which records all the info. You can also print out a copy from the digital tacho. You have to apply for a digital tacho card. Use
https://www.dvla.gov....ices/order_forms.aspx
to get an application pack (you wany STA1, second from bottom). I think it still costs £35, and of course you (not your company) have to pay. Once you have your digital card, you must carry it even if you are driving an analogue tacho vehicle, as if you get stopped Plod know you've got one and will ask to see it. My mate got done £200 as he'd left his at home by mistake!