I have been using one of your template forms (Wedding Day Questionnaire) and I can't find how to edit it after its been submitted, is this possible to

Once i publish a form, an email is received with a link to the form, I fill in and submit. Then I receive another email containing my form. However then I need to make changes, how to I edit my form and re-submit?

Make sure you are logged in to your account first at https://www.jotformeu.com/login

You can edit the form in the Form Builder by selecting the form in your My Forms list. And click on the EDIT button.

You can use this direct link also https://www.jotformeu.com/build/80236102968355

Let us know if you are still not able to edit form.