Without knowing about noise and echo, I am asking this question. How to remove/add noise /echo for a given WAV file? Please provide suggestions/guidance.
In order to "remove" noise from a signal, you must have or recreate the noise you want to remove and substract that from your audio. So it depends on whether you can isolate or replicate the problem signal.
To a certain extent "noise" (hiss or other constant sound) can be cleaned from an audio signal and there are various applications/plugins that attempt to do this - success depends on the consistency and amplitude of the noise vs signal.
Removing "echo" (not sure what you mean by this, but I assume you mean "reverb", or acoustic properties of the space the sound was recorded in) is extremely complex since it is not consistent and in most cases would be impossible to replicate.