If you have an Audio file, you can use it to create a script. Maximum length of the Audio file is 7 minutes.
In a Script
Click on the +
Choose Script
Give it a Title
Choose Format
Pick a Theme
Pick a Filter
Click "Write Script"
Open the AI script creator view
Click"Transcribe Audio"
Click "Upload Audio"
Choose file
Transcribe!
New Video
Click on New Video
Click on Audio
Click "Upload Audio"
Click "Next" to continue creating your video