how to make a diet plan ?

Combine a diet with exercise. That's the best way to lose weight and it's healthy. You can put some lemon juice in your water, it burns fat. Make sure to eat healthy. Concentrate more on eating fruit and veggies. I wouldn't recommend to lose weight quickly because then you're more likely to bounce back fast afterwards. Lose weight slow and steady. You should also check your bmi so that you keep your goal-weight healthy. Don't skip meals. Breakfast is the most important meal. If you'd like more help, my inbox is always open.

I suggest you pick a popular diet: dukan, zone, keto, etc. so you have a system already made and just have to stick to it, otherwise everybody will have an opinion on what you should do and it's going to be confusing.