If you have created a folder within the Shareable boards section, you cannot share it. But, you are able to share all of the boards in your folder and have your guests or team member create their own individual folders! To do this, you will first have to invite your guests and team members to the shareable board (*note, Shareable boards are only available on the Standard plan and up).
If you have any further questions, please feel free to reach out to our Customer Success Team at Support@monday.com! We are available 24/7 and happy to assist :)