Turkey's constitutional change bill has been formally submitted to President Recep Tayyip Erdogan for approval, parliamentary sources said on Thursday.
Erdogan will have 15 days to approve or reject the constitutional changes that would allow the country to adopt a presidential form of government.
If approved, it will be published in the country's Official Gazette, setting the date for a referendum vote.
Authorities said the referendum is expected to be held on either April 9 or 16.
The proposed changes to the constitution require a simple majority or 51 percent in the referendum.
The government says the revised constitution will provide stability at a time of turmoil.
Opponents say it will strip away checks on presidential power.