From the Files tab in your Home page or a specific space, select the plus [+] button in the upper right corner of the Add a File bar. Click the paperclip icon and choose the Link option. This will open a field where you can type the URL. After typing the website link, click Done. You can edit the people who will see this link, what space the link will go to (if adding from your Home page), and you can begin the conversation. You can also mark this link as a favorite by clicking the star icon and add notes.