If you use the attribute
edit='true', for example:
[mb_frontend_form id='my-custom-fields' post_fields='title' edit='true'], you will be able to edit the post after submitting the form.
If you want to edit the post on the frontend, please create a dashboard page with a frontend dashboard shortcode. It supports a table of posts that belong to the current user to edit/delete. Please read more on the documentation https://docs.metabox.io/extensions/mb-frontend-submission/#user-dashboard