Hello Ihavemanyquestions21,
This page can help out with maximizing the battery life, as well as the lifespan of the battery: Maximizing Battery Life and Lifespan
The page will have additional info on each step, but it will help to cover the following:
Update to the latest software.
Optimize your settings.
Enable Low Power Mode.
View Battery Usage information
Plug in and power on your computer to charge your device.
Extreme ambient temperatures may also impact battery life. On the link above it'll help to note:
iPhone, iPad, iPod, and Apple Watch work best at 32° to 95° F (0° to 35° C) ambient temperatures. Storage temperature: -4° to 113° F (-20° to 45° C).
If you still experience issues you may try reaching out to Apple Support for a further investigation here: Get Support
Cheers.