Copy
This page and all its descendants will copy the page you have chosen, and any sub pages it has.
This page only will only copy the page selected
Page Content
Create empty pages will create a copy of the page without any of the content or modules it contains.
Same content with multiple locations will create a copy of the page with the same content, but with the original page being the primary location. This means that if you edit the content on the original page it will also update for the copied page
Same content with multiple primary locations will create a copy of the page with the same content, and both pages are primary locations. This means that if you edit the content on either the original page or the copy page it will also update for the other page
Create copies of the content will create a copy of the page with the same content, but there will be no link between the two pages, so changes on either the copy or original pages will not affect the content on the other.
The remaining options are standard page settings which you can read more about on Editing Page Settings
