HIIT training burns the most calories in the shortest period of time and your body will continue to burn calories hours after your high intensity session is finished. Many say due to the high intensity, short recovery times, this is the most efficient way to burn calories.
I always include Strength training in my week, at least up to three times per week. My strength training also improves calorie burn at rest, improving your Basal Metabolic Rate (BMR).
I also include running in my week. I love running. Any form of cardio, whether its cycling, swimming or running are all great forms to build your stamina, improve your fitness levels and help to reduce % body fat.
However, as we all know and read, diet is so important. What and how much we consume determines how our body fat % is affected. That's not to mitigate other factors too, for example metabolic factors, insulin resistance, thyroid etc.
What works for me doesn't work for all, but if you're looking for inspiration, try to incorporate a balance of HIIT, Strength and Cardio in your week if your goal is solely to reduce % body fat.