All visitors to Iraq require a visa for entry. If you fly into Iraq without an entry or working visa you will be deported.
For those entering the country without a visa, one can be purchased at most border crossings for US$80. Total crossing time is around one hour for individuals.
If you intend to acquire a visa at your port of entry, be prepared for long waits, and bring plenty of documentation about who you are and what your business in Iraq is. Letters on company or government letterhead are preferred.
Obtaining a travel visa to Iraq is complicated and time-consuming. You can obtain an application at the Embassy of Iraq. However, all applications are vetted in Baghdad. Even if you do obtain a visa, you may still be refused entry into Iraq once you arrive.