In case the Attachment tab of work item does not let you drag and drop the attachment, that means that the user has no permission to perform Add Attachment action.
Such actions are controlled by the group permission the user belong to.
To correct that, please ask your system Admin to setup the permission on your group to allow the Add Attachment to the specific work item you are working on.
Answer for Why I can not add attachment to work item
Author: Rami.Azulay
Expert in deployment of lifecycle management system into Medical Device vendors who seeking warranting successful Medical Device Auditing and Regulatory Compliance through Process Automation Tools It is no secret that Medical Device companies incur much costs and organizational stress relating to creating and maintaining their Technical File, DHF or ISO documentation, especially before first time submission or external auditing by notified bodies. https://il.linkedin.com/in/ramiazulay