H Sherry,
To change your WikiTree link visibility at GEDmatch, log in to GEDmatch. On your main/home page there, click on the pencil next to the kit that you'd like to edit. Scroll to the bottom of the edit kit page to the WikiTree info, where you should be able to choose the "Enable even if alias" radio button for public availability and click the "Change" button.
If the WikiTree info indicates "No WikiTree link for this kit", you may need to wait a few days for new GEDmatch IDs that have been recently added to WikiTree to be recognized at GEDmatch.