Is it safe to use air fryer machine or halogen air fryer instead of frying using oil ? and if we are using oil for frying, which oil is the safest?

Lowering fat is good: A diet that is low is fat is very healthy for your heart so kitchen appliances that help you to lower the fat used to fry foods tend to be healthier. So, it is not only safe to use an air frier, it is healthier. Your body needs some fat though and the healthiest fats are usually monounsaturated or polyunsaturated fats like you find in vegetable oils.