Karbala and Najaf are the core of most itineraries
The Haram of Imam Hussain (AS) and Hazrat Abbas (AS) in Karbala, and the Haram of Imam Ali (AS) in Najaf, are the two anchor sites almost every package is built around. The cities are about an hour apart, so most itineraries base pilgrims in one and day-trip to the other.
Kadhimiya and Samarra extend the trip
Kadhimiya (Baghdad) and Samarra add historical and spiritual depth but require more travel time and, for Samarra especially, more caution around routing. Ask whether these are included or offered as an optional extension.
A complete quote should show visa, flights, and hotel distance
Confirm who handles the visa application, which airport you land at (Najaf is closest to Karbala), and how far the hotel is from each Haram. Avoid partial quotes that leave these details for after you've paid.