So I need to log out of apple account to set up new iPad

These support pages should get you started with setup of your new iPad - and the methods of transferring your data from 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

When you are ready, should you choose to do so, the best procedure for preparing you old device for disposal or reuse can be found here:

What to do before you sell, give away or trade in your iPhone, iPad or iPod touch – Apple Support

joannes192 Said:

"So I need to log out of apple account to set up new iPad: transferring data from old iPad to new one. Do I need to log out of my Apple account"

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No. In fact, log in to the same Apple ID on both iPads, and all would transfer like a charm.

Go Here: Transfer Data from your Previous iOS or iPadOS Device to your New iPhone, iPad, or iPod touch - Apple Support

Not that I know of. Was that a prompt or error message?