Oracle APEX is a web application development tool for Oracle databases. While most of the work is done on a web browser, when it comes to printing it relies on the generation of PDF files. These files a commonly created using an Apache FOP print server, either as standalone or embedded in the Oracle Data REST Services/APEX Listener.
The default print report layouts provided are table-like reports. In order to create a custom report you can however create your own layout using the XSL-FO language.