Brexit has resulted in major changes for visa / entry requirements for UK passport holders. The UK left the EU at the beginning of 2021, and since then certain travellers are now subject to visa requirements.
Most tourist, or business travellers, with a UK passport, can still enter the EU without a visa for up to 90 days within 180.
Some activities however are classed as work, and therefore require a particular type of Schengen or European Visa.
Some Tourist and Business travellers may also need to obtain a Schengen visa since Brexit, mainly due to the lengths of time they plan to spend in one or more EU countries.