To edit a page:
When you are done editing the source, click Apply.
Notifications and comparisons are not clear about image changes, such as when you add or edit alt-text, so consider mentioning that in a change comment.
Notifications and comparisons are not clear about changes to wiki page title, so consider mentioning that in a change comment.
If you edit a page for a particular Jira ticket, consider mentioning that in a change comment.