SharePoint and SharePoint Online actually have multiple ways to view the sites usage, most unique views, and most viewed data. This blog will walk-through each of the “out of the box” ways through Modern and Classic SharePoint.
Modern: Site Contents > Site Usage
Unique Viewers
Displays unique viewers daily across the entire site collection. Unique views are users who visit the site collection at least once within the reporting day which would not include refreshing the page or multiple visits. The chart can be filtered by Last 7 days, Last 30 days, Last 90 days.
Site Visits
Displays the amount of site visits, refreshes, or clicks across the site collection.
Site traffic
Displays weekly data when people have accessed your SharePoint site collection in the past 12 weeks.
Most Unique Viewers and Most Viewed
Shows most unique viewers and most viewed from the past 7 days from each document and page.
Most Popular Items
In classic SharePoint in the Library ribbon there is a report for the most popular items per each library.
If you notice in the url, you can see the Lists ID /sites/testsite/_layouts/15/topreport.aspx?List=%7B43B10157-CC32-4C48-A613-C6E594B21216%7D.
If you are not able to get to the classic view you can find the List ID and replace in the topreport.aspx List query. Just put the ID in between the 7’s.
This report can show you per library the items with the Most Views, Most Views by Unique Users, or Most Recommendation Clicks.
Popularity Trends per document
From the Most Popular Items view you can actually see Popularity Trends for each document over time. The report will automatically open Excel and produce a table and graph for Daily and Monthly Hits.
Popularity Trends entire site
You can also view Popularity Trends based on the entire site. By going to Site Settings > Site Administration > Popularity Trends
Site Collection Audit Settings / Audit Log Reports
Finally once you set up Audit Settings you can Run Audit Log reports on the entire site collection. As a site collection administrator you can find the settings for Audit Log Reports and Site Collection Audit Settings under Site Settings > Site Collection Administration.