Cable for iPad 10th generation does not fit I phone 13 ?

Your new iPad10 was supplied with a 20W USB-C Power Adapter - along with a USB-C to USB-C cable with which to connect the iPad for charging.

As with all current models of iPhone, your iPhone has an Apple Lightning connector - and will use a matching USB to Lightning cable. Your iPhone may have been supplied with a USB Type-A to Lightning cable, which cannot directly connect to USB-C connections.

To charge your iPhone using your new Power Adapter, or to connect your iPhone to your iPad, you will need a USB-C to Lightning cable:

• USB-C to Lightning Cable (1m)

https://store.apple.com/uk/xc/product/MM0A3ZM/A

The new iPad 10th generation uses a USB-C Charge Cable. The iPhone 13 uses a USB-C to Lightning Cable.

Apple changed the iPad from USB-C to Lightning Cable, to a USB-C cable as part of the move to the later standard.