How many calories should I eat in a day to lose weight (19, female, 5'10, 185 lbs)?
Your approximate Total Daily Energy Expenditure (TDEE) is 2000 calories. TDEE is how much energy your body uses for physical function such as breathing, circulating blood, digesting food, or physical movement.
Creating a deficit here you will lose fat.
The deficit can come by way of reducing your food intake by 500 calories daily. Or from reducing calories AND burning calories by way of some kind of exercise.
I find it easier to start with one. Either start by reducing calorie intake and slowly introduce exercise or by starting exercise and then introducing calorie intake limitations.
Hope this helps.