I have created a form but when I email it and complete the form I can't send it back?

I am not sure what you mean by "send it back".  If you are trying to send email confirmations when the form is submitted, these are our guides on setting up email notifications.  The first is on setting up notifications sent to you:

http://www.jotform.com/help/25-Setting-Up-Email-Notifications

The second is how to setup notifications to your users:

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder

If there is something else you are looking for, let us know a bit more detail regarding your needs and we will be happy to assist you further.

Hi,
Please can you advise me further on the following.
I have created a form and then as a test I sent it to an email and
completed it.
Do I then have to save it and attach it to a reply email or is there a way
that once I have completed it I can just click a send button etc.
Regards
Karen
...

What you can do, if I understood you right, is to share link of your form to whoever you need, and set up Notifier in your form so whenever the form is submitted you receive an email with that submission.

You can get the link of your form by going to Publish in form builder:

And then just copy the link or share it:

You can setup the Notifier as well, and you will receive filled submission of your form every time somebody submits it.

If you need any additional assistance or you had something else in mind please let us know.

Thank you!

Please can you tell me how they have to submit the form when completed.
Thanks
Karen
...

I have checked your account to verify the form you're working with. I found out that the form does not have a "Submit Button"

If I'm understanding your concern correctly, you would like to send a link to your form to the email address of your form respondents. 

So your respondents can submit your form, I suggest you add a submit button to your form.

After that, send the link to your form via email.

How-to-send-a-form-via-email

Your respondents will receive it then they will need to click the link to your form from the content of the email. Once the form loads, they fill it in and submit it. 

I hope this helps. If, in any case, I misunderstood your concern, please feel free to contact us anytime. Thank you.