How is the Census Conducted?
Although Census Day is officially observed on April 1, 2020, the count will begin before then. The 2020 Census will be the first time that households have the option of responding online, by mail, or by phone. In mid-March 2020, most households will receive an invitation in the mail encouraging you to respond online. Areas with households that are less likely to respond online will receive paper questionnaires with their invitation. Responding by phone is also an option. Beginning in May 2020, the Census Bureau will follow up with households that have not responded.
[Source: U.S. Census Bureau]