To avoid upsetting customers, you may have to rethink the delivery terms e.g. DAP or DDP (see Pricing and Payment Terms). These clarify who is responsible for customs clearance and paying any extra shipping costs, tariffs and import VAT (and that it is clear to both parties how much this before any sales are agreed).
Delivery expectations should also be set to take into account any delays that may occur due to the requirements for extra documentation and customs checks.
B2C Considerations
Some of the biggest immediate impacts are being felt in UK companies selling to EU consumers via online marketplaces. Most major marketplaces will block sellers to the UK or EU if their goods are not first cleared through customs and VAT checks. For example, if you are selling into the EU via Amazon you must take immediate action to ensure that you are blocked on Amazon’s Fulfilment By Amazon (FBA) program. This will require you to ship the goods to an Amazon EU fulfilment centre (in either: France, Germany, Spain, Italy, Poland and the Czech Republic) pay EU import VAT (and any applicable tariffs) and complete the export and import declarations before sales can be made.
You should note that VAT requirements also apply to B2C EU sales of electronic services.
B2B Considerations
The outline requirements relating to documentation and VAT for UK EU trade in goods are listed above. If you trade in services, you should check out the UK government’s guidance on selling services to the EU, Switzerland, Norway, Iceland and Liechtenstein