Definition
A form submission is the combined event and payload produced when a user completes and submits a web form. The payload includes the field values the user entered. The event is what your server does in response: validate, persist, notify, integrate. Modern form-submission pipelines are much richer than just "save the field values" - they capture metadata (timestamp, IP, user agent, referrer) and trigger downstream actions (emails, CRM updates, webhook calls).
Because form submissions are often the top of the funnel, what you capture about each submission determines what you can measure downstream. Skimping on metadata capture (no UTMs, no referrer) makes attribution impossible later when you have revenue data to join against.
How SheetLinkWP relates to Form Submission
SheetLink Forms treats every submission as a rich event. The captured payload includes: the fields the user filled, submission timestamp (in your site's timezone), full UTM set, GCLID/fbclid/msclkid, referrer URL, landing page URL, IP address (optional), user agent, consent text, and a unique submission ID. All of this is written to your Google Sheet with dedicated columns, so downstream analysis has everything it needs.