Descript

Descript lets you edit a podcast or video the way you edit a document. It transcribes the recording, and deleting words in the transcript cuts them from the audio and video. It can remove filler words, clean up voices recorded in noisy rooms and generate captions, which makes it a common first stop for podcasters.

On the music side it includes a stock library and lets you lay music under speech on separate tracks, with fades and ducking. Keep music low enough that dialogue stays clear, and check the license of any track you bring in from elsewhere. If you use its synthetic voice features to patch words, use only your own voice or one you have permission for. Export a mix with the music and voice on separate tracks if you plan to master it elsewhere.