The Power icon on the taskbar notification area is your battery level indicator for your Windows 10 device (ex: tablet or laptop).
When you hover over the Power (battery) icon, you will only see a percentage of battery life remaining by default.
When you click/tap on the Power (battery) icon, you will see a percentage of battery life remaining, a link to Battery settings, and a Battery saver action button to toggle on and off.
If you like, you can enable to see the battery life estimated time remaining shown in hours and minutes along with the percentage. The estimated battery life remaining time is calculated and made in real-time, so it can fluctuate wildly.
This tutorial will show you how to enable or disable showing the battery life estimated time remaining for the Power icon on the taskbar for all users in Windows 10.