My old Azure DevOps Organization has multiple projects and I'd like to export and import the Azure DevOps Project between the organizations, especially the Work Items in Boards.

I came across the Microsoft document -

CSV file was not been uploaded directly, it was firstly been parsed and then put it into the request.

It is obviously unrealistic to use such a request because it is too complicated.

A feasible solution is to use the REST API to get the workitems information, and then save this information to a CSV file. Then read the CSV file information and fill it into the REST API of Create Workitems.