On this tab you can enter notes or comments related to the activity for which you are using the timer.
Memo:
Enables you to add a memo to the time entry
by typing unlimited text or using Auto
Complete shorthand codes. You can enter important notes related to
the time entry. Click Date/Time stamp 
to add a date/time
stamp to your memos. Right-click in the memo to make use of the many functions
available (for example, cut, copy, paste and undo).
Flag 1/2/3:
When selected, they indicate that the time entry is flagged. The flags can be used to track any characteristic of the time entries that you want. Example: You can use a flag to mark time entries that are tax deductible. The label for the flags can be modified in Custom labels screen.