At the end of this year, the UK will officially leave the European Union, four years after the referendum vote in 2016.
Though not all changes have been agreed yet, there are some things that will change immediately for everyone from January 2021. Some matters - such as access to fishing waters - have not yet been decided.
These are some of the changes you can expect to see in 2021.
From January, travel to any European country - as well as to Norway, Switzerland, Liechtenstein and Iceland - will be a little more complicated than it was before.
You'll need to make sure you have at least six months left on your passport when you travel, with the exemption of travelling to Ireland.
If you have a European Health Insurance card, it will no longer be valid, and you'll need to purchase travel insurance instead. You may also need extra driving documents, depending on the country you're visiting.
The guarantee of free roaming on your phone while abroad will end, but so far no UK mobile firms have announced plans to bring back charges.
If you're bringing a pet abroad, the current pet passport scheme will no longer apply.
Your experience of border control will change, too - you'll use separate lanes from EU, EEA and Swiss travellers. You may be asked to show your return ticket and prove you have enough money for your trip.
You won't need a visa for visits to Schengen area countries. This area includes most EU nations, along with Switzerland, Norway, Iceland and Liechtenstein. From 2022, UK nationals will have to pay for electronic authorisation to travel to the Schengen area, however. You're able to visit for up to 90 days within an 180 day period
January 2021 will see the end of free movement in the EU for UK residents. This means that moving abroad will require more paperwork than it did previously.
If you're already living abroad, you'll have certain protections under the withdrawal agreement - but you should check the country's rules carefully. It may be that you need to apply or register for residency, meet specific requirements for staying or get new documents.
In France, for instance, UK nationals will require new residence permits to stay.
In airports, you'll be able to take advantage of duty-free shopping when returning from the EU in 2021. The amount of alcohol and tobacco you can bring back with you will be increased.
However, there will no longer be tax-free sales of goods like clothing and electronics in airports. VAT refunds for visitors to UK shops from overseas will be removed, too.
New rules for EU citizens
EU citizens living in the UK will have the same rights as before until 30 June 2021.
After this, you'll have to check if you can stay - you'll have to apply to the EU settlement scheme or become a UK citizen.
In Scotland, Wales and England, exporters and importers alike will have to make customs declarations.
Certain products, such as live animals and some foods, will need to be labelled in specific ways or need special licences.
There is more uncertainty around how trade will work in Northern Ireland, which borders EU member the Republic of Ireland. The government has said full guidance will be published by the end of December.
January will see the introduction of a new points-based system for immigration, similar to that used in Australia.
The government says non-EU and EU citizens will be treated equally, and that the system aims to attract people who can contribute to the UK economy.
Visas will be required for people hoping to move to the UK to live work or study. Tourists from the EU, EEA and Switzerland won't need a visa to come over for up to six months.