Because of these factors, not all external storage options will work. The latter limits some drives based on the amount of power they draw. The former affects which file system a drive can use, since iOS only reads from ExFAT, FAT32, HSF+, and APFS drives. While the Files app does work with external USB drives and SD card readers now, support is limited due to two factors: iOS and the Lightning connector. But before you try to connect your favorite card or drive to your iPhone, there are a few things you need to know. Before, it was limited to local and cloud-based files, but now you can access data from external storage devices, including SD cards and USB drives. The Files app received a big update in iOS 13.
