There are different methods you can use depending on your personal preferences. Tech-savy folks prefer using apps to keep track of their macros while others feel safest with the good old pen and paper approach. When you start out on keto, tracking can be really helpful. But as you learn more about the keto diet, you'll find that tracking our macros isn't necessary anymore.
A few apps you can use for macros tracking include: Cronometer, MyFitnessPal, Carb Manager, MyFatSecret and Stupid Simple Keto.
Whichever app, or method you use, just make sure you are tracking NET carb - total carb minus the carbs from fiber.