Hi Bruce
If you want to hide these information, you will need to edit code. Look at the file components/com_osmembership/view/emailtemplates/tmpl/email.php, you should see the code and can remove it
Also, once the modification is done, please move the modified file to PATH_TO_TEMPLATE/html/com_osmembership/emailtemplates folder so that the change won't be lost when you update to future releases of the extension
Regards,
Tuan