If you are migrating to the UK or out of the UK, establishing your domicile and residency status affects the amount of tax you have to pay.
HMRC’s guidance notes distinguish between Domicile and Residency:
“Your domicile’s usually the country your father considered his permanent home when you were born. It may have changed if you moved abroad and you don’t intend to return. Whether you’re UK resident usually depends on how many days you spend in the UK in the tax year.”
In practice this can be a very complex area and getting the right advice will ensure not only that you are compliant with the law but also paying minimum tax.