iPhone storage

You can manage your storage --> How to check the storage on your iPhone, iPad, and iPod touch

Go to Settings > General > Storage & iCloud Usage under STORAGE go to Manage Storage. It will then show the apps that are using your storage listed in order of usage.

Then focus on the apps with the most storage and delete data as appropriate. Large videos and podcasts that take up a lot of storage, can oftentimes be deleted because you can usually download them again if you want view them.

Note: deleted photos are not necessarily deleted from the phone. You may have to go to Photos > Albums > Recently Deleted and delete them from there to truly free up storage.

Let us know how it turns out.