There is no citizenship question on the 2020 Census.
The census questionnaire asks how many people are in the home at the time you complete the form; their name, sex, age, race, ethnicity; their relationships to one another; phone number; and whether you own or rent the home.
It's worth mentioning here that the information you provide on the census can’t be shared with any other government agency, law enforcement or landlord. No one. The answers you provide are used only to produce statistics. You are kept anonymous.
The census will ask if each person is of Hispanic, Latino, or Spanish origin and a person’s race. The Census Bureau asks this question because responses help create statistics about this ethnic group. This helps federal agencies monitor compliance with anti-discrimination provisions, such as those in the Voting Rights Act and the Civil Rights Act.
You can explore the census questions and why the Census Bureau asks them at 2020Census.Gov
You can also see a sample copy of the census online.