For an annuity, where she is getting regular payments, then what they send out is the RMD, and all of it is the RMD.
The only time only part of it is not an RMD, is if she is able to make a separate removal of part of, or the entire remaining balance in whatever fund it is in. Most pensions do not allow that, and some commercial annuties allow it, but then they never get any payouts anymore.