Hi Leonardo,
as long, as you fly a scheduled Timetable flight, and you do not fly it on ProPilot, of course you can file it with the PIREP page. In case you fly on ProPilot, then FlighLogger must run in the background, and it will make the PIREP for you automatically.
By charter, if you think of an own flight that is not existed in the EuroHarmony timetable, then it is forbidden.