You can archive a project if you have a Starter plan, Growing Business plan, Organization plan, or Enterprise plan subscription.
The owner or an Admin of the project can do this from the “Projects” tab of your workspace. 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 any time, 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.