How do i reattach my rearview mirror that fell off?

To reattach your rearview mirror, first clean the mounting area on the windshield to remove any old adhesive. If the mirror uses a clip, simply align it with the bracket and press it back into place. If it was glued, apply a strong adhesive suitable for glass, like epoxy or silicone adhesive, to the mount and press it firmly against the windshield for the recommended time. Allow the adhesive to cure as per the manufacturer's instructions before using the mirror.