Irish people will be quizzed about smoking, internet devices, commuting and childcare in the next census.
The new list of eight questions, which was approved by the Government, will come into effect in two-years time.
The public will also be asked about renewable energy sources, internet access, working from home and volunteering.
When the next census takes place on April 18, 2021, people will also notice 25 updated questions relating to religion, disability, ethnic groups and the Irish language.
CSO senior statistician Cormac Halpin said: "The value of the statistical information provided by the census cannot be overestimated.
"It drives policy, targets services where needed and informs our decisions at a time of continuing social change.
"There is an international element to the next census as every other EU member state will also be required to carry out a census in 2021.
"With less than two years to go, the preparations are well underway and securing government approval for the date and questionnaire marks a major milestone for census 2021."
The CSO held a public consultation in 2017 and received over 400 suggestions on possible changes to the next Census.
Members of the public, Government Departments and academic communities were among the groups who contributed submissions.
The Census Advisory Group considered the suggestions before testing them in a survey call The Pilot.
Around 10,000 people from seven counties were questioned when the survey was carried out in September 2018.
The results of it, which will be published in the coming days, led to the recommendations of the changes that will be seen in Census 2021.
Speaking on Wednesday, Mr Halpin said: "Today’s publication brings to an end a phase of work that commenced almost two years ago with the public consultation.
"I would like to take this opportunity to thank all of those who made submissions, and those who served on the CAG.
"I also want to record my appreciation for the thousands of people who participated in and those who worked on the Pilot last year.
"Their combined efforts and support have helped to produce a census form with many changes, that will provide a rich source of information on our society and economy, including important new areas and issues such as renewable energy, smoking and working from home."
The next census will also include a Time Capsule for the first time, which will enable people to write a voluntary and confidential message which will be securely stored for 100 years.
