The League Reports screen (League Menu >> Basics section >> Newspaper >> News Listing tab >> League Reports tab) includes links to a variety of reports about your league:

Use the Select League Report drop-down in the upper right corner to select a report. Several of the more common reports are also accessible by navigating to League Menu >> Info and Reports.

There are over twenty league reports available in OOTP. We won't go over them in detail here. Just explore!