Reporting is a big subject.  It involves multiple departments, approaches, and massive amounts of data (which must be correctly applied and interpreted).  Technically, the reporting happens as a dance between 3 areas:

• Dashboards
• Source Data and Organization of this Data
• Permissions

Depending on who needs the data, it may be presented in Dashboards, Lists, or both.

Depending on who needs the data, the source may be a folder, or a list.

And depending on who needs the data, permissions (usually view-only) may need to be given on lists or folders.