Hi,
Sure, check out file ‘mappress_api.php’, function ‘_mapp_directions_html’.
There’s a filter as well: ‘mapp_directions_html’.
You can try hardcoding the start location (I’m assumng that’s what you want to do) here:
<input style='width:90%' type='text' id='{$options->mapName}_saddr' value='' />
As a heads-up, in the next release the filter will be removed and the directions form will be in a separate ‘template’ file. You will need to copy the template to your theme directory and re-apply any changes there (but only once).