There will not be a question on citizenship on the 2020 Census.
The proposed citizenship question asked: Is this person a citizen of the United States? The options included No, not a U.S. citizen.
The questions was proposed on March 26, 2018, then challenged in court.
The Census Bureau states "These statistics are essential for enforcing the Voting Rights Act and its protections against voting Discrimination." - Questions Planned for the 2020 Census and American Community Survey
However, documents have been presented in court showing that "A high-ranking Census Bureau official privately discussed the citizenship question issue with GOP redistricting strategist Thomas Hofeller in 2015, according to emails cited in a new court filing in the legal battle over the potential census question....Citing an unpublished study by Hofeller, the plaintiffs have argued that the administration actually wants a citizenship question in order to give Republicans and non-Hispanic white people a political advantage when new voting districts are drawn after next year's census."- Emails Connect Census Official With GOP Strategist On Citizenship Question, Hansi Lo Wang, NPR
The Supreme Court ruled to block the question on June 27, 2019.
Department of Commerce v. New York ( (link is external)18-966) 6/27/2019
The Secretary did not violate the Enumeration Clause or the Census Act in deciding to reinstate a citizenship question on the 2020 census questionnaire, but the District Court was warranted in remanding the case back to the agency where the evidence tells a story that does not match the Secretary’s explanation for his decision.
The decision was made to have the census forms printed without the citizenship question.