Hi,
By default the borders of modules are deactivated as it's normally the template which displays the border of the modules.
However, you can edit the css file of the style and uncomment the CSS related to the board of the module you want in order to get it on your website.
For example, for the border around the currency switcher module it's that CSS:
/*************************/
/*Curency switcher module*/
/*************************/
/*module style
.moduletable-switch{
background-color: #fff;
border: 1px solid #817651;
color: #333;
margin: 15px 0;
padding: 10px;}
.moduletable-switch h3{
padding-bottom:5px;
margin-bottom:10px;
border-bottom: 1px dashed #817651;
color:#817651;
}
*/
So you should remove /*module style and the last */ of that code. Then, you will need to make sure that the class of your module is moduletable-switch. You can configure that with the "module class suffix" option of the joomla options sreen of the module.
Note that you can edit the style's CSS via the Display tab of the configuration.