This text usually appears in the header of your webpage.
NOTE: Before applying any changes, always remember to take a backup of the previous state.
Answer:
Click on **Extensions->Template Manager
**
The Template Manager page will now open, click on the name of the relevant template “The template that is selected for your site”
Click on the Edit Html button
Search and Remove for the following line/s
<a href="<?php echo $baseUrl; ?>/"><?php echo $mainframe->getCfg('sitename') ;?></a>
or
<?php echo $mainframe->getCfg('sitename') ;?>
Click on the Save button
Refresh your webpage and the sitename text/link should be gone. NOTE: If the changes to not take effect, try to clear the Joomla! Cache