Can a folder be shared?

Yes, folders can be shared for both Envelopes and Templates but they act a little differently, here is a DocuSign article on the topic of Shared Envelopes and how this can be setup by your DocuSign Admin. You did not specify whether the "share" was envelopes or Templates so I was a vague to cover both....

https://support.docusign.com/en/guides/ndse-user-guide-document-folders

Here is an article on shared Template folders...

https://support.docusign.com/en/guides/ndse-user-guide-use-shared-templates