If you want to make a copy of a page / post in WordPress, you need to install a “Duplicate Post” plugin from https://wordpress.org/plugins/duplicate-post/
For this you can either download zip and then upload or go to from dashboard “Plugins -> Add New” in “Search Plugin” type “Duplicate Post” and hit enter. You will see “Duplicate Post” plugin By Enrico Battocchi”, click “Install Now” and “Activate“
Once the plugin is activated, and if you want to duplicate a page, from dashboard sidebar, click on “Pages” -> “All Pages”,
Now for example, if you want to duplicate “Home” page, click on “Clone” as shown in below image,
once you click “Clone” you will see the same page getting duplicated, just below that page, with default settings as “Draft” as shown in above image.