The forums ran from 2008-2020 and are now closed and viewable here as an archive.
Home › Forums › Back End › button › Reply To: button
The log-in button is an actual input but the registration is just a link.
input
As this is Joomla, I think you would need to edit the theme (much like WordPress / Drupal) so if you cannot do this yourself you would need to speak to the developer.