Use of different text changes for Text Type

Hi! I know how to use text changes option such as P (Log) and R (Display Log). However, I am curious about the other options available. Does anyone know the differences between these

<blank> Edit

C Display

A Paste

?

If I want to keep the original value that I enter the text for (the relevant text type), which should I use? Blank for 'Edit'?

Also, if I use P, does that mean if I need to write report to show the value for different text type, I would not be able to do so since all these texts are kept in the Log rather than under the respective text type?

Appreciate any help on the above.

Cheers!
SF