what is the difference in public and private form

secondly, what is the difference in public and private form. I do not want my form to accessed by generally public using url. I have embedded my forms in wordpress where user can only fill form after log in

Hi again,

Making the form public means that anyone with your form's link gets to access your form and make a submission. For private, forms are only accessible to those who are invited via an email invitation link. If you have embedded the form on your WordPress site, I would suggest setting it to public so it will be visible to the page.

Let us know if you have further questions.