I assume that you're asking to add text to the body of an email. To accomplish this please follow the steps below:
Step 1: Navigate to the Main Settings & Administration page
Step 2: Under Alerts & Reports select Manage Reports
Step 3: Select the Schedule Manager (It's to the right of Report Manager under the Manage Schedules header)
Step 4: Select the report you want to modify and edit
Step 5: Navigate to the Actions section and Add Action
Step 6: Select Email and Configure Action. Enter the text desired in the Message box.
Hope this is the information you were looking for.
I run a Daily report under NCM that backs up the configs. The report is then emailed out and needs to have a classification within the body of the report. Currently I'm running NCM 7.3 which may not have the ability to perform this function. I am able to perform the actions you listed above however, the report I run is not generated or listed in that menu..