Battery showing wrong percentage

First, go to settings>battery>battery health

If this percentage is below 80% your battery can be replaced

You can try to fully discharge the phone and after that fully charged and leave it on the charger for a while This will calibrate the battery

You may get better and prompt responses if you may kindly provide the iPhone Model that you have and the iOS version if it is known to you and re-post.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

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Please re-post with detail so that someone else can help.