Management Reporter CU15 added the ability to print from the web viewer. This allows those viewing the report to send the report to a printer for archive purposes or for further review. See the annotated screenshot below for more information on this feature.
You will then be prompted to download an XPS file. You then use Windows 7 or later XPS viewer to open the download and send to the printer. Windows 10 also includes a PDF printer, so if you would like to save the file as a PDF you can download the XPS file and then click File | Print and select the PDF printer.