The best way to export your projects from Projects is via the print property or by sending them via mail. You can do this by tapping or clicking on the name of the project. Then scroll down to the "Action" section.
If you prefer your project or folder as a CSV, click here to learn more.
To export as a JSON file, select the appropriate field in the Actions section.
Decide in the following window if you want to add the comments and/or the archived tasks (green means included). If you had activated a filter before opening the menu, you can also decide whether you want to export all the tasks or only those of the filter.
Once you have added and selected everything you want, click on "Generate JSON". You can either copy the file to your clipboard or download it.