If your phone is running Android
6.0 Marshmallow out of the box, you won't be able to customize the Quick Settings panel as the phone is using native Android
's Quick Settings which doesn't allow this. You will need to update the phone to Android
7.0 Nougat or later—if the update is available—to be able to customize the Quick Settings panel.
However, if your HTC phone is running Android 5.0 Lollipop and you update it to Android 6.0 Marshmallow, you can still customize the Quick Settings panel as the HTC phone will retain HTC's Quick Settings which allows customization.
To check the Android version of the phone:
- Go to Settings, and then tap About.
- Tap Software information.