i wonder, i have created a custom post type form for email submission.

i wonder, i have created a custom post type form for email submission. I was thinking that do they also get saved in any of my wp directory also. The forms are submitted to external post type to external url. Is there any trace submitted email left?

I'm not sure, that goes out of our scope of Support I'm afraid.

That depends on how your external URL is processing the data that you're sending from the form (on submit) and how that script is created.