Since: 5.1

Create own email template is very easy. Add following code in your child theme’s functions.php (or in any custom plugin)

add_filter( 'fep_eb_templates', 'fep_cus_fep_eb_templates', 10, 2 );
function fep_cus_fep_eb_templates( $templates, $where ){
    $templates['my_custom_email_template'] = 'My Custom Email Template';
    return $templates;
}

Note key ( my_custom_email_template ). Create a php file same name as my_custom_email_template.php and add in your child themes front-end-pm/emails folder ( See more ).

Now go to Dashboard > Front End PM PRO > Settings > Emails and select your template from dropdown. Now every time any email sent will use your template.