Hello @Milyelara, welcome to the community! Your question was translated to English, since this is a international forum.
I'm sorry to hear that! Is this a new behaviour or something that you experienced for a longer period? I suggest that you charge your phone to 100% and then use it down to 15-10%. Then go to Settings > Battery > Show Battery Usage and check what uses most of your battery. It's important that your phones battery is below 15% to get a fair result.
You can also reboot your phone in safe mode, to make sure that it isn't caused by any of your downloaded applications. In safe mode, all third party applications are temporarily inactivated, but you can still use all basic functions like calling and messaging, accessing the Internet and using the camera. To exit safe mode, just restart your phone as usual.
Keep me posted, and have a nice day!
