The president's approval came eight days after the parliament sent the amendments for his approval after passing it by more than the 330-vote threshold needed to send it to a referendum.
Deputy Prime Minister Numan Kurtulmus said that the referendum "is planned to take place on April 16".
Turkish President Recep Tayyip Erdogan signed a package of constitutional amendments which would establish presidential form of governance in the country if approved at a referendum, Erdogan's administration said Friday.
The constitutional change will bring a shift of regime change in Turkey with a strong partisan presidential system that will take over all authorities of the prime minister and cabinet.
The post of prime minister, now held by Erdogan loyalist Binali Yildirim, would be replaced with one or more vice-presidents.
Ankara accuses Gulen of orchestrating an attempted coup in Turkey last July.
Aguero says Man City future to be decided at end of season
I don't think we deserved to win but a draw would have been fair". When you're on the bench you have to wait for your opportunity. He needs few training sessions to be ready.
NAN recalls that on Jan 19, the two largest opposition parties in parliament say the 18-article bill, which could enable Erdogan to rule until 2029, will fuel authoritarianism in the North Atlantic Treaty Organisation member and European Union candidate country.
Erdoğan says the reform will provide stability at a time of turmoil and prevent a return to the fragile coalitions of the past.
If the proposed changes to the presidential system go ahead they will mark a crowning achievement for Mr Erdogan, whose AK party has already begun campaigning for a "yes" vote before the official campaigning period begins.
"Can Turkey be dragged into an unpredictable adventure?" "We believe that our nation will substantially say "yes" to this proposal".
Erdogan, the most powerful Turkish politician since founding father Mustafa Kemal Ataturk, became president in August 2014, in the first ever direct elections for a Turkish head of state.
The new 18-article constitution would create an executive presidency similar to the system in the United States and France.