The exclamation point (!) on the toolbar. Enter or note missing client info, q’s, etc.

I think Client Status has a place for things like that, doesnt it? 

The Client status button is at the very top of the Fed Info Worksheet

You can also make notes in each field, just click on pencil at top menu

I usually don't enter specific notes, but I'll right-click and "Mark as Estimated" if I want to come back to something.

Client Status sheet has two sections for notes: 1) for this Current Year's Comments that only stay in this year's file, and 2) Permanent Comments that carryover to next year's file.