Exempt tax for an order while creating in admin

While creating orders in admin backend, is there any way to exempt tax?

I’ve searched through the docs and many tax extension around, but there are only ways to configure tax exemption for “customer group”, “product group” or … there is no way to set tax free for a specific order, which is being created by admin.

Anyone have any thought or idea on this? Any extension that works similar or code snippet or hints would be helpful too.

Thanks