The below step are given with considering report already exist. Not for new report.

Step1: Select report and go to design mode.

Step2: Create c/al global variable. Example: Status := Boolean 

Step3: Now go to View -> Report Page

Step4: Set SourceExp=c/al global variable, name=any name and  caption = which you want to see as a label

Step5: Go to code method onprereport/initreport and show as a message

Example: message(format(status));

Step6: Now run the report and check parameter has set. Checked or unchecked your status and see the message.