Every form in a CommCare application can be identified by a unique value called an XMLNS. This value usually looks like a URL starting with "http://openrosa.org/formdesigner/" and is used in various places throughout CommCare - including exports and APIs - to identify the form and corresponding data submissions.
You can find the XMLNS for any given form in a number of ways which should all produce the same result.
In the Application Builder
Open your form in the Application Builder and from the hamburger menu choose "Edit Source XML". From there look for a variable defined on the <data> XML attribute called "xmlns". You do not want one that has "xmlns:jrm", "xmlns:orx" or any other value.
In the below (abbreviated) example, the XMLNS value is "http://openrosa.org/formdesigner/3BAC6D49-D1A2-4D41-A39C-DAA034326670".
From a Form Submission
From the Submit History report, open any form of the type you are trying to look up. In the "Raw XML" tab, look for the same xmlns attribute on the <data> XML tag of the submission.
In Data Exports
Go to your Data exports page and create a new export using the form you are trying to look up. Then look for the URL parameter called "export_tag" in your browser's URL bar.