Hi Keung C,
A business needs a valid EORI number to move goods between Great Britain (England, Scotland and Wales) and other countries. You can use below service to check if an EORI number beginning with GB (issued by the UK) is valid.
Check an EORI number
The Customs Declaration Service supports making import and export declarations when moving goods into and out of the UK, you will need an active subscription if you are looking to Import/Export goods.
Subscribing your Government Gateway user ID to the Customs Declaration Service will allow you to do things such as:
• submit import and export declarations using software
• get your postponed import VAT statements or get your import VAT certificates so you can complete your VAT Return
• pay Customs Duty and import VAT
You do not need to subscribe to the Customs Declaration Service again if you have already done so for either imports or exports.
Thank you.