This is a Lightning adapter that allows you to transfer files to USB 3.0. For example, you can plug in a USB stick and transfer the files. It supports exFAT FAT32 & NTFS! This product only supports exFAT FAT32 file system format, so no NTFS!
The standard format of USB drives that are purchased is usually exFAT. It supports IOS 12, 13 and higher.
What the adapter can also do is, for example, plug in a Type C to USB 3.0 on the adapter and transfer files to your iPhone, iPad. See product photos for more details.
You can also use it for charging. The so-called Reverse Charging. See product photos for more details. What it does is it takes power from the other phone and supplies power to the other phone. Note this is very slow. This is a nice addition.
Finally, it can also recognise mice and keyboards via the USB receiver of a mouse or keyboard. You can then, for example, connect a mouse with a USB receiver and use it on your phone.