On many phones under the latest versions of Android the charge percentage is not displayed by default in the status bar. You can check it only even your device is currently charging or you pull down the drawer So you can see only a circle showing you the remaining energy. Here is how to show it on Android 7 and 8. The screenshots taken from Google Pixel.
- Pull down the drawer.
- Tap and hold the gear icon:
- Wait while it is spinning until you see “Congrats!…” In such a way you will add System UI Tuner to Settings:
- Go to Settings.
- Tap on System UI Tuner:
- Select Status bar.
- Enable Always show percentage in Battery:
Now you can see the charge percentage in the status bar: 