I do not know the name of this effect but I want to use this effect on my audio. Can you please tell me how to do this using audacity. I think it is a kind of echo but I don't know the decay factor and time. Click here for the audio
As in the answer above this is called a Reverb effect.
I have written some steps below in regards to replicating the effect from the song you posted:
1) Open Audacity, click File -> Open -> Locate the file that you want to apply the effect to 2) Press Ctrl + A to select all 3) Click on Effect -> Gverb 4) Tweak the settings and click on preview to hear what it sounds like 5) Once you happy click on OK and your done :)
Heres a youtube video if your still unsure:
I only listened to a short segment, but what I heard is an effect called "reverberation" or "reverb" for short. I don't know audacity, but I'm sure it has a number of reverb effects. The reverb in this recording can probably be approximated with freeverb, which is very likely included in audacity. You will have to tweak the settings until it sounds the way you want it to.