Hello @VDiaz123072 ...
I'm not sure if you are an instructor or a student. If you are a student, this will depend on whether or not your instructor has a setting turned on/off which allows for editing. Specifically, the setting is, "Let students edit or delete their own discussion replies". You'd have to check with your instructor to see if he/she has that option turned on or off.
If you are an instructor, the option I've just described above can be found in the course "Settings". Here are a couple Guides that describe this:
I hope this helps to answer your question. Sing out if you have any other questions about this...thanks!