Help:Edit summary
What summaries are for
An edit summary is a short note saved with a revision. It helps readers understand the change in page history and recent changes. Describe the edit, not your opinion of another editor.
Useful examples:
Added a source for the system's discovery dateCorrected link to the station articleReverted unsourced change; see discussion
Avoid empty or vague summaries such as update, and do not claim a change is verified unless you checked it. If the edit only affects one section, identify that section or use the automatically supplied section label if present.
What to include
Keep the summary accurate and concise. Mention the reason where useful, such as a citation, formatting correction or response to a discussion. Do not put private information, personal attacks or lengthy explanations in it. A summary is not a substitute for explaining a disputed content change on the discussion page.
You can usually add a summary in the edit form before saving. The field length and controls depend on the site interface; check the displayed limit rather than relying on a particular character count. Preview the page and summary if the editor provides that option.