A
fajita is made from grilled meats, vegetables, dressings (like guacamole) and eaten by rolling it all up in warmed tortillas with beans and rice on the side. A fajita is pretty much finger food.
A
buritto is generally larger and more ambitious. It is a large tortilla, filled with meats, vegetables, cheese, dressings, beans, and or rice, then rolled up tight. They can be eaten with fingers but it is usually too big - fork and knife are often needed.
Fajita
A common Mexican-American dish that is traditionally made of skirt steak marinated in lime juice, oil, garlic and red pepper then cooked. The meat is then wrapped in a flour tortilla and garnished with things like grilled peppers and onions, guacamole, sour cream and cheese. Other meats like chicken, fish or shrimp can be substituted for steak.
Burrito
Burritos are a traditional Mexican food that was designed as a portable, ready-to-eat meal and often packed into saddlebags. They consist of a filling, usually made up of any combination of cooked, ready-to-eat ingredients like meat, a sauce, refried beans, and cheese, which are wrapped in a flour tortilla.
See also:
https://en.wikipedia.org/wiki/Fajita
See also:
https://en.wikipedia.org/wiki/Burrito