It is, necessary to register for an EORI number to have customs clearance for shipments to/from non-EU countries including The United Kingdom past this date.
That means Tariff codes, country of origin and EORI on non-EU shipments
You can register for an EORI number at http://indberet.virk.dk/
It will basically be your CVR number with DK infront of it. Click the logo below to read more.
How to add it in Webshipper
To add your EORI number to your sender information,
go to Settings > Locations > Customs numbers > select the type you wish to register and enter the number. Finally click "add" and the number is added to your shipping info.
Read more about EORI from each carrier below.
For further details, see links below