If you don’t want to save all entries that were submitted on your web form, you are definitely looking for a way to approve them before saving them in the Submissions table. Here’s how you get there:
Go to the Settings → Advanced section of your form and check the option Request approval of submission. Here you can select to send the request for approval to one or multiple email addresses. If at least one recipient approved the submission, it will be automatically saved in Submissions.
Another option you can choose is to let form users approve their submission, as a double-opt in system. Works well with newsletters or other events that require an email check. Select the form field that contains the user’s email address in the dropdown. Don’t forget to set the field as required, otherwise some form users might leave it blank and the submission will never be approved or rejected.