Hello,
First you have to find the the value of the parameter used for a specific trace.
Left mouse click on the plot label in the waveform window, e.g. V(VF). Now a cursor (cross hair) is attached to this V(VF). Move the cross hair cursor to the trace you want? with the up/down arrow-keys of your keyboard.?
Now when you move the mouse cursor over this cross hair cursor, you will see a 1 (first cursor) or 2 (secoond cursor). Then right mouse click and LTspice will report the parameter used for this trace.
"Cursor 1: Temp=10? Run 2/6".??
Finally you can add this information, e.g. 10¡ã, to the trace in the waveform plot as a comment.
Plot Settings -> Notes & Annotations -> Aa Place Text
It might be a good idea to change the text color to the color of the trace.
Finally save the plot setting.
Plot Settings -> Save Plot Settings
If you need an example, then let me know.
Best regards,
Helmut