An estimated 650,000 people from the armed forces and police are eligible to casts their ballots on April 13.
The early elections are being conducted in only 12 of Iraq's 18 provinces, due to security concerns.
These are the first elections Iraq has held since parliamentary elections in 2010.
On April 20, an estimated 15.5 million Iraqi citizens will have the opportunity to cast their ballots.
There are concerns this poll might aggravate sectarian problems, especially after the Shi'ite-led government delayed voting in six provinces, two of which are Sunni-majority areas and the other four are in the northern Kurdish region.