Message Scheduler is a messaging app that allows you to schedule messages on a specific date and time.
Its not a reminder app. This app will actually send your message on the scheduled date and time for you. The app does not need to be running when the message needs to be delivered. You can send regular (immediate) texts as well.
If the receiver does not have this app, a regular text message will be sent.
You can cancel scheduled messages any time by deleting them.