This assign is to set form display.

I like to know how to set values from inputs into message (mail script).

I have the following:
<p>
<label class="input1">Familiy name</label>
<input id="text1" name="{$varname}" size="60" maxlength="60" class="required" />
</p>

and assigned:
$smarty->assign('varname', $_POST['varname']);