Only users with "Edit" or "Manage everything" permissions can delete documents from a space.
To delete one or several documents, a user can select them from the Content tab of the workspace, click on Delete and confirm. The documents are moved to the Trash tab of the workspace (available to users with management rights only) and will not appear in the workspace's content list anymore. Their lifecycle state is now "deleted".
A user can also delete documents using right-click on the document's icon from the Content tab of the workspace.