Urgent help needed

I’ve recorded a piece of speech but can’t remove or soften the hissing in words containing final “s” sound. What can I do?

Try using the “Equalizer” effect to lower the “sss” frequencies.
If you select the “sss” and use “Analyze > Plot Spectrum” you will probably see a marked peak somewhere around 3000 Hz (switch the Plot Spectrum “Axis” setting to “Log Frequency”). It is this peak that you need to reduce.