In plain language
It stops bad data, such as a missing email or a negative quantity, from flowing into other systems.
Example
A workflow rejects a form entry when the email is invalid and asks the submitter to correct it.
Related terms
Schema · Filter · Parsing · Regular Expression (Regex)
Common misconception
Validating in the form alone is not enough; data also arrives through imports, APIs, and edits that skip the form.
Implementation guidance
Validate at every entry point, check required fields and formats, decide whether to reject or quarantine bad records, and report why data failed.