Audacity

Audacity is a free, open-source audio editor that runs on Windows, Mac, and Linux. You can record narration directly into the software, edit out mistakes and background noise, add fade-ins and fade-outs, and export in multiple formats. It supports multi-track recording if you want to layer background music or sound effects under your lecture.

It's ideal for instructors on a tight budget who need to record voiceovers for video lessons or create standalone audio content. Compared to paid tools like Adobe Audition, Audacity has a steeper learning curve but no licensing cost and no recurring fees. It's particularly popular for podcast-style course content and correcting audio quality issues in existing recordings.