If you have an EU wide or single community approved exporter authorisation
HMRC will automatically transfer your EU wide or single community approved exporter authorisation to a UK only authorisation with effect from 1 January 2021.
HMRC will not send out a new authorisation letter so you must keep your existing authorisation documentation in your records. For single community or EU wide authorisations any special conditions that relate to the approval will no longer apply.
If you wish to export goods from EU countries directly, you must check if you are eligible and apply for approval in those countries.
Applying for approved exporter authorisation from 1 January 2021
You can continue to apply for approved exporter status using form C1454. HMRC will consider your application and when approved will issue an authorisation letter.
For new trade agreements, the UK is moving away from approved exporter authorisation towards a system of self-certification using the EORI number as the identifying reference.
If you don’t already have an approved exporter authorisation, you’re unlikely to need one unless you intend to export on a regular basis under one of the transitioned agreements.
Source HMRC Guidance