How to remove Echo from videos

Hello everyone,

I am developing my first e-course and almost near to completion.

However, while testing my videos, I am now realizing that there is a lot of echo in my audio.

I am done with all of my recordings and now a bit worried about how to remove this echo.

I will be grateful if anyone can help me with some solutions to fix this problem.

I have using DaVinci Resolve for editing my videos and Audacity for audios.

Thanks