It is pathetic that Canon is unwilling to explain how this can be achieved. It's a simple (minimum 6 steps, possibly more) procedure that will save your remaining hair from being pulled out.
1. Home
2.Menu
3. Output report
4. Report settings
5. Fax TX result report
Now, the fun begins. Typically, the choice "Error only" is highlighted. "Off" and "On" are not highlighted. When you press "On", nothing happens.
You have to select the "Error only" option, illogical as it may seem. Then, you will be able to say "Off" to it. (You may want to say something different but only "On" and "Off" are available.)
Then you can return to 5. Fax TX result report, select "On", and, after a few more steps, it will be saved.
The whole thing has been designed by idiots who have never needed to sign an important document and verify transmission..