WebApp Version
Drag your mouse over the top left corner of the project then click on the "i" icon to access your project settings.
Click on the "Archive" button at the bottom left of the screen.
Your project is now archived.
You can see how to restore a project in this article.
Android Version
Go to the list of your projects
Click on the 3 vertical dots next to the project you want to archive.
Click "Archive"
🚨 IMPORTANT NOTICE🚨
When you archive a project it is automatically unsynchronized!