Ok, I have added a custom field for profiles, but the default is just a single short line. I want to make this a large box similar to the "Bio" box. I know it should be fairly simple, which template and what would I change?
You'll have to change it in editbasic.php cause the extra-fields are formated there and not in the templates.
Around line 149 find:
if ($config['extra2']) {
$extra2 = "
{$config['extra2']}
<br />
<input type="text" name="Extra2" value="$Extra2" class="formboxes" />
and change it to:
if ($config['extra2']) {
$extra2 = "
{$config['extra2']}
<br />
<textarea name="Extra2" cols="$TextCols" rows="$TextRows" wrap="soft" class="formboxes">$Extra2</textarea>
You may want to put in customs values for "cols" and "rows" to fit the size to your needs.