To check the visa requirements, you will need to provide information about where you are moving from and the purpose of your visit. If you’re an EU or EEA national, you won’t need a visa to work or live in the UK. This facility applies for an unlimited time with no requirement to register or apply for a permit. This situation will change after Brexit and the transition period (31 December 2020) and will have implications on the number of removals to the UK. People arriving from outside the EU/EEA, Canada, Australia or the US require a visa to enter and work in the UK. They should apply at the UK embassy before travelling.
If you are working in the UK, you will need to register and pay taxes with HMRC. Your employer should do this for you, but it is essential to check that you are registered. It allows you to pay tax and National Insurance. National Insurance contributions entitle you to state benefits like the coveted NHS, historically the first health service “free at the point of delivery” in the world. Before you move, you may also want to look at opening a British bank account to make it easier to make and receive payments in your new country.