One of the configuration options available on the right sidebar of every Content Type form is labeled Scheduling options.
This is the Scheduler tool. Scheduler gives content editors the ability to schedule nodes to be published and unpublished at specified dates and times in the future.
Note: If you select a Publish on or unpublish on date, you must also select a time.
If you select either, you must also select an Publish/Unpublish State.