If you want to storyboard and have a reference of the voice-overs BEFORE recording the actual actor's voice, you can SUBTITLE your viewport using OBJECT to TEXT in Blender.
In this video, we will walk through the basics of text editing to create objects to be used as a text for subtitling storyboard sequences directly on the viewport.
Check the video tutorial here: https://youtu.be/zFcJzEc3zq8
Download the FREE FILE below: