The following actions are available to users who have an Administrator or Editor role. Editors have access only to the forms in their own section of the site.
You can edit the title and main text at the head of the form from the "Edit" tab. You can add or change fields on the form from the "Webform > Form components" tab. You can determine who will receive email notification when a form is submitted from the "Webform > E-mails" tab. You can determine to which page the user will be redirected (if any) after submitting a form from the "Webform > Form settings" tab.
The information submitted by people who submit the Webform can be viewed, and exported as csv (e.g. Excel spreadsheet) file from the "Results" tab. Any spam submissions can be deleted individually. Once a set of results has been downloaded, or at least after the closing date, it would be a good idea to use the 'Clear' link to delete all results.
Once the closing date has passed, you may wish to unpublish the form.
These tabs will of course not appear for end users of the site, or even for a logged-in user whose has not been granted permission to use these features.
Some spam is inevitable. There is a built-in spam protection feature which is invisible to the user, and tends to more a lot more effective than the 'Captcha' method used on the current site. If spam proves unmanageable we can look at more heavy-handed anti-spam solutions.