What type of usage are you wanting to look at.
If minutes and texts and data then as above use the App.
If how you've used your data then most smartphones have built in Data Monitors. These give breakdowns in what app has used what.
In an iPhone it's under Settings -> Mobile/Cellular ,and look at the Apps at the bottom which show what's used how much data. Remember to Reset the Stats at each allowance refresh so you get an accurate reading.
Current Phone >
Samsung Galaxy s²³ Ultra 512gb Phantom Black.