The UK-EU Trade and Cooperation Agreement ensures that UK firms in a variety of service sectors can continue to access the EU market, including as business travellers and cross-border services suppliers or investors, while being treated no less favourably than either EU businesses or competitors from third countries.
While the Agreement sets out expectations of the treatment and level of access to each Party’s domestic market, there will still be some changes for business as a result of no longer operating under European Economic Area (EEA) regulation covering cross-border trade in services. These changes are different for each sector and differ in each member state of the EU.
For Government guidance for UK businesses on rules for selling services see: https://www.gov.uk/guidance/providing-services-to-any-country-in-the-eu-iceland-liechtenstein-norway-or-switzerland-after-eu-exit
There are country guides and information for UK businesses providing services and travelling for business to countries in the EEA and Switzerland: https://www.gov.uk/government/collections/providing-services-to-eea-and-efta-countries-after-eu-exit