UK citizens can no longer apply for a new European Health Insurance Card (EHIC).
If you have an existing EHIC, it will continue to be valid until its expiry date.
Once it expires, you'll need to apply for a Global Health Insurance Card (GHIC) which provides access to state healthcare in the EU.
EHIC and GHIC do not replace travel insurance.
It is strongly recommended to take out travel insurance with medical cover when travelling abroad.