Southern Illinois University Carbondale
Step 1: Sharing is done at the group level, so if you want to share a single reference, a few references, or your entire library you have to put them into a group.
Step 2: You share references with EndNote Online, so the next step is to sync your EndNote Desktop library with your EndNote Online library (or create an EndNote Online account) by clicking the Sync button in the Desktop toolbar. 
Step 3: From the Help menu choose EndNote Online and EndNote Online will open in your web browser.
Step 4: Click on the Organize tab in EndNote Online.
Step 5: Check the Share box to the right of the group you want to share and then click Manage Sharing.
Step 6: Click Start sharing this group and enter the email addresses with which you would like to share the group. You must use the email addresses that the other person(s) use for their EndNote Online accounts.
Step 7: Manage the sharing options; choose Read only or Read & Write. Read only allows users to view the references only and Read & Write allows users to edit and delete references from a group (note: references deleted by another user will remain in your library either in another group or in your unfiled references).
Step 8: Click Apply.
Step 9: Shared references will appear in the My References tab in EndNote Online under the heading Groups Shared By Others.