The term physical distancing is the act of standing 2 meters (6 feet) away from other people. Physical distancing also includes a broad set of measures encouraging people to refrain from shaking hands, avoid crowds, and most importantly staying at home if you feel sick.
Isolation is for those who are already sick and is meant to protect the healthy people by keeping the infected in confinement. Isolation is critical to avoid the spread of the virus.
Quarantines are recommended for families, groups and communities in order to separate and restrict movement of people who may have been exposed to COVID-19 to see if they become sick.