Am I required to register in the UK?
You do not need to register if you are going to leave the UK before 31 December 2020. You must, however, register if you want to continue to live and work in the UK after the transition period ends on 31 December 2020.
How to regsister
You can register by applying for settled status or pre-settled status in the UK before 30 June 2021. Go to gov.uk for information on what you must do to continue living and working in the UK. See also Can I still live and work in the UK after Brexit?