The 2020 Census is part of the decennial census program mandated by the US Constitution. The decennial census is used for apportioning Congressional seats, as well as many other purposes, such as demographic research, allocating funding, and informing public policy. The 2020 questionnaire is short, covering these topics:
data.census.gov is the main data portal for US Census data. It contains data from the 2010 decennial census as well as the ACS from 2010 to present. New updates to census data will be available through data.census.gov