Your employer should be handling the landing visa (for arrival) and your residency visa paper work (after you arrive). Have you asked them what you need? It is unusual too that you are purchasing your plane ticket. Commonly, the employer provides you with your ticket - all you need is a valid passport with at least 6 months to run after your date of arrival. Additionally, usually the employer sends you a copy of the landing visa for presentation at immigration once you arrive (and for presentation at the airline where you board your flight to Qatar).
Suggest strongly you contact your employer and ask them these questions.
Your employer should be handling the landing visa (for arrival) and your residency visa paper work (after you arrive). Have you asked them what you need? It is unusual too that you are purchasing your plane ticket. Commonly, the employer provides you with your ticket - all you need is a valid passport with at least 6 months to run after your date of arrival. Additionally, usually the employer sends you a copy of the landing visa for presentation at immigration once you arrive (and for presentation at the airline where you board your flight to Qatar).
Suggest strongly you contact your employer and ask them these questions.