The most common ways to track your carbs is through MyFitnessPal and their mobile app. You cannot track net carbs on the app, although you CAN track your total carb intake and your total fiber intake. To get your net carbs, simply subtract your total fiber intake from your total carb intake. I have written an article on How to Track Carbs on MyFitnessPal.
Others choose to use FatSecret or cronometer. If you ask the Keto for Beginners Community “how do you track your carbs on keto?” You’ll be flooded with a chorus of MFPs (MyFitnessPal) and Cronometers. Mostly people are aware of such apps. The choice is totally up to you and up to your own free will to decide about its usage.