If your iPhone does not show the battery health after replacing the battery, a pop-up prompt will appear: "This iPhone battery cannot be verified as a genuine Apple battery. Health information for this battery is not available. This may be because your battery is not original. If your battery is not authorized and the data does not support it, the word "maintenance" will not be displayed even after replacing the third-party battery.
If your iPhoneXS or above is replaced with a third-party battery, the word "Maintenance" will not be displayed after replacement. This does not mean that the mobile phone battery is faulty. If your mobile phone is below iPhoneX, some brands of batteries support the display of health after battery replacement.