Can I use a global autoresponder

Hi,

Thank you for contacting us.

What are you referring with "Global Autoresponder " ? 

You can set an autoresponder by following this guide, it will send the email to your submitter, if you want also receive an email notification, you should set an email notification, this email will be sent only for the email addresses that you specify : http://www.jotform.com/help/25-Setting-Up-Email-Notifications 

If it does not help, please, provide us more details, we will be glad to assist you.

Regards.

Is it possible to use one responder for several forms for easier editing

No that can not be possible, you can only set one autoresponder per form, if you want to make some changes then you need to open the form and then edit the template of the autoresponder.