Go to MacUpdate.com and search for "network usage monitor".
View Usage History to see your Mac notebook computer's battery level, how much energy your Mac has used, and how long its screen was on. You can check either the last 24 hours or the last 10 days. Choose Apple menu > System Preferences, click Battery , then click Usage History.
For Mac users, look for the Console app, which you can use to view your logs. When it opens, you'll see "All Messages," and you scroll up to go back in time. For Windows users, open the Event Viewer.
View how much mobile data you're using To see how much mobile data you've used, go to Settings > Mobile Data or Settings > Cellular.
Checking App Data Usage in iOS
Open the Settings app and tap Cellular, near the top of the list. Then scroll down to the list of all your apps and find FaceTime in the list. Under the name of the app, you'll see how much data it's used this billing period.
To check and manage data usage, from the home screen select the Settings app. Note: To check your current month's data usage dial *data# (*3282#) on your mobile phone to receive a text message with the current bill cycle's usage.
Open the Phone app on iPhone and navigate to the Keypad tab. Then dial #3282 (#DATA) with the pound symbol included and press the green Call button. You should get a message right away with your current data usage for this billing cycle.
Press Settings. Press Mobile Data. The total data usage is displayed below MOBILE DATA USAGE. The data usage for each application is displayed below USE MOBILE DATA FOR.
How to check your cellular data usage on an iPhone
Open your iPhone settings.
View & Manage Data
Go to Settings > Network & Internet > Status, click “Data usage,” and then select “Enter limit.” Under “Limit Type,” you can choose whether you'd set the data limit to reset monthly with the “Monthly option” or after a certain number of days with “One Time.” Enter how much data you can afford in either MB or GB in the
You can see the amount of system memory being used on your Mac. In the Activity Monitor app on your Mac, click Memory (or use the Touch Bar) to see the following in the bottom of the window: Memory Pressure: Graphically represents how efficiently your memory is serving your processing needs.