How can I find my form to edit it ?

To edit the Form submissions you can do it via your submission page. Here is the guide to do it:

https://www.jotform.com/help/325-How-to-Edit-Submissions-Made-on-Your-Forms

https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

To edit the Form to add/update the Form fields you can go to the Form builder:

My Forms page>>select the Form>>click on edit.

Let us know if you have further questions.

Thanks.