⚠️ It's not possible to archive projects on the Free plan.
You can archive a project from the “Projects” tab of your workspace if you're the Owner or an Admin. Hover over a project and select “Archive project” under the Settings menu:
Archived projects are still stored in the cloud, but they're not accessible to you or your teammates. You can reactivate them at anytime, as long as you have a subscription with enough project slots.
☝️ For the organization projects, members with an Editor or higher role can archive them.