There are several ways how you can export your map.
You can export it as an image: what you see on the whiteboard gets exported in PNG, SVG or PDF. Click the cogged wheel button on the top menu bar, then go to the "Map actions" section. There, you can scroll through various export options.
Exporting as text - including all your pinned notes.
Select the concept of your map that should serve as the heading of the exported text. Then click the three dots and "Download as text." The text will be exported in the Markdown syntax and will include all pinned notes.