For both template edits, it depends on the skin you are using.
THE BEST THING YOU CAN DO RIGHT NOW is to learn how to use Webmaster Mode and identify the template(s) used for the page you want to edit.
http://help.x-cart.com/index.php?title=X-Cart:Using_Webmaster_mode
Using webmaster mode, you will see that you probably have a template, <skin_name>/customer/bottom.tpl
And in bottom.tpl. it calls
<skin_name>/customer/phones.tpl
Depending on what your goal is, you can comment out the call to phones.tpl, or just the tel displayed.
{* this is commented out in a smarty template *}
this is not
/* this is a multi-line comment in a php file
the comment-out block continues until the
*/
// this is a commented out single line in a php file
I hope this helps.
J