How to REMOVE audio noise?

How do I filter out a continuous static-noise on a file, it goes for the entire length of the mp3.

You’re probably best served by an audio editor, not a video editor, to manipulate audio. Audacity is one example of a free open source multiplatform program, and it has some ability to reduce noise, either using its traditional noise reduction effect or a newer AI effect (which I have not tried, and which has some limitations).

Try the noise gate or notch audio filters.

Thank you notsmooth and Dan (great program - have made over 300 youtube videos with shotcut!)! Found this video to help me with what I needed.