There are two ways to remove a project:
Archive it - the project still shows up, and you can still open it to see information. But you cannot make changes to the project.
Delete it - the project is removed completely. The project information is not kept, and it cannot be restored.
The steps for archiving and deleting a project are similar:
On the top bar, click the Projects list, then click MANAGE PROJECTS.
On the project card, click Options > Archive or Delete.