A picture would help, as Zenith63 said. Is it a fixed head coming out of the wall at above head height, or a rigid pipe coming out of a mixer at hand height, going up to a curve with a head (so you would be replacing the fitting at hand height.)
If the latter, it should be simply a case of unscrewing one and screwing on a flexible pipe with shower head (and fitting on the wall to hold the showerhead. These are readily available. You might need an adaptor, but again, readily available
Even a link to what yours looks like, from a website, would be handy. Easier to find than taking and uploading a picture.