Statistics Canada held a presentation on July 24, 2020 which provided information on the 2021 Census of Population questionnaire, including some of the changes made since 2016.
From Statistics Canada:
This presentation gives an overview of the topics discussed during the virtual roundtables on the 2021 Census of Population questionnaire content. The five main topics are the following: family, demography and activity limitations; languages, ethnocultural diversity and immigration (including citizenship, religion, population groups, minority language education rights); Indigenous peoples; education, labour, commuting, and Veterans; and housing, income and expenditures.