For teaching music online or presenting your Noteflight score to others you can use Google Meet or Zoom to share you computer audio.
For Google Meet, you can share your Chrome tab with audio so others can hear your Noteflight score playback. Here is how it works:
1. Use the "Present now" option in Google Meet and select a "a Chrome tab" for sharing:
2. Select the Chrome tab with your Noteflight score from the menu of options, and make sure the "Share Audio" option in the bottom left is checked:
3. Everyone else on Google Meet will see only this tab and will be able to hear the audio playback. Make sure every "Pins" the view of your tab on their screen so they can see it in full view.
For Zoom, please read the Zoom Sharing Computer Audio article.