To help slow the spread of the virus governments are using a variety of restrictive measures.
Quarantine and isolation are both used to restrict the movement of those that are known or thought to be infected , have been in close contact with those who are infected or have come from an area they deem to be high risk from SARS COV-2.
Isolation - separates sick people who are ill from others who may not be to stop the virus from spreading.
Quarantine- separates and restricts the moment of people who have or may have been exposed to the virus
In the UK if someone has symptoms of COVID-19 or tests positive then they need to self-isolate for at least 10 days, in addition anyone that they have been in close contact with and their whole household is asked to self-isolate for 14 days. Self-isolation means that you must not leave your house.
Some countries have also restricted travel coming into and out of the country from high risk areas. The borders may be closed completely or you may be forced to take a test and/or to isolate for up to 14 days upon arrival to ensure that you are not carrying the disease.
Restrictions on social gatherings
Other measures such as restrictions on where people can go at which times of day (e.g pubs and restaurants) or how many can meet up an home outdoors or inside can be used to help stop the spread of the virus. These can also be used on a local/regional basis when infections start to rise. These can be expanded leading to full lockdown when infections get too high.