Sharing between your own devices works the same as sharing with somebody else.
- On your first device, create a sharing invitation from the list you would like to share
- Tap (…) in the top-right corner.
- Tap > Share
- Tap Share Changes to List
- Choose how to share (e.g. Messages).
- Send the invitation to yourself so you can open it on your second device. For example, send it via Messages to yourself.
- On your second Device, tap the invitation link.