Along with calories, the MyNetDiary Free version supports tracking up to 108 nutrients per food entry, ranging from simple ones like Sodium and Iron to complex Omegas. You can check the available nutrients in your mobile app under Me - My Weight Goal and Plan - Nutrients tab.
To customize the target - find the required nutrient and tap on it - choose Daily Target Value and enter the number. Then you can customise it's visibility to display in your Food Log or Dashboard.