You can pass links on the fly by just pasting it into the chat window. If you'd like to have a link available in your campaign for your players to access at any given time, you might want to consider making a journal entry - either with a character or a handout to house the link. Just add the link inside the offered text box (not the GM Notes text box). Also, make sure you assign permissions to either All Players or selecting specific players so they can see the entry in their own journal tab.
