You can make a fact shared only if it's a new fact type that you're setting up. Shared means it belongs to a couple - married or partners.
If you want to copy a fact to someone else (any number of people), right click on the fact and click copy from the drop down menu. Then right click again, click paste and you'll get a dialogue box showing relatives that you can select to receive the fact. If it's not a relative, than navigate to the person and right click, paste and follow the dialogue box.
This is one of the powerful features of FindMyPast.
Good Luck
Martin