Hello anneliramolins,
Thanks for posting in the Apple Support Communities.
We understand that you're having issues with apps closing unexpectedly. If you haven't done so yet, try following the troubleshooting actions provided in If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support.
It's also a good idea to take a look at the battery health for your iPhone, since this can affect how your device performs. Use the steps below to locate and check this information:
- Open Settings > Battery
- Tap Battery Health & Charging
- Look at the Maximum Capacity and Peak Performance Capability
If the maximum capacity is showing 80% or less, it's likely time for a new battery. You can read full details about this in iPhone Battery and Performance - Apple Support. If needed, reach out to Apple Support to discuss your options at Get Support.
Best regards.