Depend on witch block You are using.
This is an example on the Random news block.
Fist step is to create a copy of the default templates.
Select the Admin menu.
Select System Admin
Select Templates
Clone the Default templates and give it any name you want.
Select System Admin
Select Preferences
Select General setting
Change the “Default template set” to the new set you just created.
Now lets edit.
Select System Admin
Select Templates
List Templates for the News module (under You new set of templates)
Find news_block_randomnews.html and click View
<table>
<tr>
<td>
<ul>
<{foreach item=news from=$block.stories}>
<li>
<{if $block.sort=='counter'}>
[<{$news.hits}>]
<{elseif $block.sort=='published'}>
[<{$news.date}>]
<{else}>
[<{$news.rating}>]
<{/if}>
<{$news.topic_title}> - <a href="<{$xoops_url}>/modules/news/article.php?storyid=<{$news.id}>" <{$news.infotips}>><{$news.title}></a> <br /><{$news.teaser}></li>
<{/foreach}
</ul>
</td>
</tr>
</table>
Change code to
<table>
<tr>
<td>
<ul>
<{foreach item=news from=$block.stories}>
<li>
<{$news.topic_title}> - <a href="<{$xoops_url}>/modules/news/article.php?storyid=<{$news.id}>" <{$news.infotips}>><{$news.title}></a> <br /><{$news.teaser}></li>
<{/foreach}
</ul>
</td>
</tr>
</table>
End by submit.
That’s it.