Docs are awesome but it's always better to try it on your own
You are literally just one click away!
Default report for all worklogs created within last 30 days.
Daily report for last 30 days set as a smart period.
Example of a report with data pivoted based on users and worklogs, not issues. That may be helpful if you have long lasting issues with multiply worklogs entries.
Sampe report based on issues from multiple projects
Pivot Report allows you to visualize the data using several chart types.
Jira time tracking is kind of in place, but not really an easy thing to use. But luckily for you Pivot Report can help with better display of spent time.
Another example of the Pivot Report power: Capacity tab. It helps you get something meaningful from the due dates in issues. Original Estimates per assignee are mapped to periods like a month, two weeks, etc. with an option to split period by days.