Given a region in frequency domain highlighted in different color , How can we get that region back in time domain? or location in time domain

Question

I have one signal in frequency domain which has some highlighted portion as an anomaly, What I would like to do is that convert this frequency domain signal with highlighted region into the time series domain and anomaly region as well. Is there any way I can do it. I used the following code for time to frequency domain conversion

    '''data = pd.read_csv(path)
    y= fft(data)
    
    sample = len(data)
    N = 96000 # sampling rate
    frequency = np.linspace (0.0, sample, int (N/2))
    y= 2/N * (y[0:np.int (N/2)])'''