Stay calm - there's an easy fix!
If you're having issues with Google Docs/Sides/Sheets, follow this link to go straight to your site settings for Google Docs:
Or this link for Classroom:
(if the links don't work, you should be able to find these within Chrome Preferences > Site Settings > Microphone > search "Docs" or "Classroom".
Below is a screen shot showing the Chrome settings page – do you see something similar, with ‘Allow’ for microphone?
If not, please change to ‘Allow’.
Now refresh your page, and you will be able to access the microphone.
If the setting already says Allow, please try quitting and restarting Chrome, and then try to record a voice note in Google Docs.
Still not working?
Please go back to the Chrome settings page, and change the microphone setting to ‘Block’, and then refresh the Google Doc page, before trying again.