Standard reports are curated reports available to all users. They serve as commonly used reports, sample reports to get started on building customized reports, and sample reports to showcase certain reporting capabilities (e.g. a new data column, a new type of visualization).
Standard reports don't need to be created as they are available by default.
To locate the standard reports, go to the "Manage reports" page, the standard reports will be listed under "All" reports. If you would like to only see standard reports, you can select "Standard Reports" on the left hand panel.
For an overview of all available standard reports, see 2 Available Standard Reports.