One way is to use conv() to smooth/blur the signal:
windowWidth = 9;
kernel = ones(1, windowWidth) / windowWidth;
smoothedSignal = conv(signal, kernel, 'same');
That is basically fitting the output element to the mean of elements in the sliding window. If you want it to follow the signal less closely, you can use a wider window.
Or you can use a Savitzky-Golay filter, done by sgolayfilt() in the Signal Processing Toolbox. I'm attaching a demo for you Mona. This is similar to conv() in that it does a fit in a sliding window, but you can specify some order of polynomial to fit to data in the window. For example, you can fit a quadratic or cubic function to the data in the window and assign the middle element to the fitted value. So with this filter, it's still a local filter but you have more control over how much you want to smooth or follow the original signal.