Duplicate Post is a plugin for WordPress which allows you to clone a post/page with its fields. It’s released under GPL v2.0 or later.
You can download it or learn more on its page hosted by WordPress.org Plugin Directory.
If you find this useful, please consider donating whatever sum you choose, even just 10 cents. It’s been downloaded thousands of times: just a few cents from every user would help me develop the plugin and improve support.
You can use this PayPal button:
There are two other ways to contribute: