Sometimes it may be necessary to insert a link to an online document from within Workspace. The process of inserting a link to an online document hosted in Teams/OneDrive/SharePoint/Google is similar to uploading a document:
1) In Workspace, click on the blue 'Add' button on the right hand side.
2) In the subsequent form, DO NOT upload a document. Instead enter the URL in the alternative field. See screenshot below.
P.S. please contact Helpdesk if you need help extracting the URL from a document hosted in Teams/SharePoint/OneDrive/Google and to also verify that the intended recipients have the necessary read/write permissions on that document.