What is the difference between usb to lightening and usb-c to lightening

They are different connections, and on supported iPhones using a USB-C wall adaptor, the USB-C cable offers faster charging.

"Connect your iPhone, iPad or iPod with Lightning connector to your usb-c– or Thunderbolt 3 (usb-c)–enabled Mac for syncing and charging.

You can also use this cable with your Apple 29W, 61W or 87W usb-c Power Adapter to charge your iOS device, and even take advantage of the fast-charging feature on iPad Pro, iPhone 8, iPhone 8 Plus, and iPhone X.

Compatible with the following computers:

12-inch MacBook; 13-inch MacBook Pro — Thunderbolt 3 (usb-c); 15-inch MacBook Pro — Thunderbolt 3 (usb-c); 21.5-inch iMac — Thunderbolt 3 (usb-c); 27-inch iMac — Thunderbolt 3 (usb-c)"

https://www.apple.com/ca/shop/product/MK0X2AM/A/usb-c-to-lightning-cable-1-m

The difference is the port they plug into. The USB-to-Lightning plugs into a USB port. The USB-C to Lightning plugs into a USB-C port.

Both plug into a lightning port.