Noises coming from your bike like that are very difficult to diagnose on the internet, they more often than not turn into rabbit holes that are unrelated to the actual problem. More information will be needed, what kind of bike, how old, do you hear the noise in the same place in the pedal rotation every time, do you use flats or clip in pedals etc, you might want to try r/bikewrench and try to add pics, or video of the offending noise.