Markdown Exporter for Confluence allows users to export Confluence pages to Markdown, lightweight markup format.
If you haven't installed, please install from Atlassian Marketplace here: https://marketplace.atlassian.com/apps/1221351
Once installed, you can use this add-on from page action icon (...) on the right.
Click on Export page to Markdown to open add-on window.
It will start converting page to Markdown. Once finished, you will see a link to download Markdown file.
Click on Download Markdown file to download exported page to your local computer.