Hello Louise Gough
The Government has confirmed that the VAT place of supply rules for services will remain broadly the same for UK businesses when the Transition Period ends on 31 December 2020.
Except there will no longer be any distinction in treatment between supplies with the EU and those with countries in the rest of the world.
Invoicing requirements will remain the same. UK businesses will no longer be required to complete an EC sales list when supplying services to businesses located in the EU.
Further information on services can be found in VAT Notice 741A: Place of supply of services (VAT Notice 741A