best method for transferring data from old to new device

The “best” method is subjective - and will reflect the method that best suits your own particular circumstances.

These support pages should get you started with setup of a new iPad - and the methods of transferring data from an old to new iPad:

Set up your iPhone, iPad or iPod touch – Apple Support

Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support

Use Quick Start to transfer data to a new iPhone, iPad or iPod touch – Apple Support

If the donor iPad, from which you are transferring your data precedes iOS12.4, QuickStart will not be available.

“Transfer” is rather a misnomer. In reality, your data and setup is merely cloned to the new device. Nothing is moved or removed from the original device.

An alternative is to restore either an iCloud or iTunes backup to the new device:

How to back up your iPhone, iPad and iPod touch – Apple Support

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Make a full backup to your computer (https://support.apple.com/en-us/HT203977) and then set up the new iPad using that backup. https://support.apple.com/en-gb/HT204184