Custome note on report (same as managewp)

Hello, once upon a time i was using managewp.
That was before finding out mainwp which is way better on many point.

But i miss a functionnality.

on managewp you can add custom note to your client account, each note has a date.
And when you export a report it include all the note within the chsosen date range.

How could we do something similar ?