How do car website generate automatic prices?

Some scrap car websites when the customer provide their car details (car reg plate number) it automatically comes up with their car. And generates a price. I believe this is linked to the DVLA. But not quite sure. The price I’m guessing goes off the kerb weight of the vehicle. 1 example of site that has this feature are https://www.scrapcarnetwork.co.uk/ . does anybody know how this is done? I’m interested in I putting this into my website. Thanks for any help.