WPEForm can show notices to users, if they have already submitted a form. This is useful to give a nudge to your users about their previous submissions, or asking them to edit their submission, instead of adding a new submission again.
The configuration can be access from Form Builder's Permissions Limits.
Enable Submitted Notice
Enable the switch Show notice if submitted.
A new control Submitted notice will appear here. In the Rich text editor you
can use the special anchor href value
%LAST_SUBMISSION_LINK% which will be
converted to the link to the Summary Page of the last submission.
Now when your users view the form, a notice will up as the image on top.