I am 22 yrs old with a weight of 45 kg and a height of 5'2". I am skinny, but I have belly fat. How can I best fix that with diet and exercise?
For your nutrition, eat at a caloric maintenance every day (which can be estimated with a TDEE Calculator), the goal of which is for the number on the scale to stay the same. For your training, exercise your entire body and do your sets to or close to failure to ensure that your muscles are being challenged, this is to ensure that they grow as a result. The result of these simple directions is that your body fat percentage will decrease while your muscles become more notable and toned.
If by any chance you are worried about getting too bulky from exercise, don’t be. It takes quite a bit of time to add muscle to the body. If at any point you feel like your muscles are too big, you can easily relax your training. As a more tangible example of what I mean, a man might expect to gain 1-2 lbs of muscle at best over the course of a month, while a woman might expect half of that. Also, you’ll want to be following a competent workout plan that is in line with your goals, not having a plan is a really bad idea and you’ll progress much slower.