The UK government has launched a series of advisory guidance for European businesses who sell either goods or services to UK companies which will kick off from the 1st Jan 2021 when the end of the transition period ends.
The information is available in different languages and cover:
Buying and Selling goods
Paying VAT or claiming VAT refunds
Transferring personal data to the UK
Providing services in the UK
For more information, please visit the UK Gov website