Whenever a form is validated with success, a confirmation message must be provided. This message must remind the user of the action that has been executed.
Note
In some circumstances, a confirmation message is not necessary, as the page displayed after submitting the form makes the result of the action obvious. For example:
A connection form that sends the user to a “User profile” page.
A “Go to next step” button that sends the user to the next step in a form with multiple steps.
A comment form that sends the user to the comment posted.
Etc.