I use diabetes:m it was called something better but they changed it! It's awesome though, you can log everything in it and set reminders etc. I'm on android so don't know if it's available for apple.
I use carbs & cals it's good if you're only just learning how to carb count but it gives an accurate number of how many carbs are in a meal/snack ect I did pay for it but it's very helpful!