BlueMail lets you act on an email directly from its notification, without opening the app.
To customize which actions appear, go to Settings | Global Settings | Customize Menus | Configure Notification Actions. Tap the ( + ) icon to add an action, use the drag handle to reorder, and tap X to remove one.
Available actions include: Archive, Delete, Done/Undone, Forward, Read/Unread, Reply, Reply All, and Star/Unstar.
