OneNote gets "speech to text" Transcribe
The Transcribe option is coming to OneNote for Windows to let you get a “speech to text” written transcript of either a live recording or an already saved audio file.
It’s an extension of the existing Transcribe feature in Word on the web (in a browser) and works the same way. That’s not entirely a good thing because Microsoft has done nothing to fix annoyances in the current Transcribe.
See Convert a recording into text with Word’s Transcribe
OneNote’s Transcribe is on the far-right of the Home tab.

For details of how Transcribe works see Convert a recording into text with Word’s Transcribe
There’s also a chapter in Dictation and Read Aloud in Office about Transcribe.
Limitations
Originally Transcribe had a limit of 300 minutes per month but that’s changed.
At the moment there’s no limit on the amount of Transcription done but Microsoft counts the minutes and might apply a limit in future.
Only Microsoft 365 customers get Transcribe except government licence users (GCC/GCC-H/DOD).
Who gets it?
Transcribe is currently available for Insiders v 2211 build 15729.20002 and later with OneNote desktop (what Microsoft insists on calling just “OneNote”).
Supported languages
Here’s Microsoft’s list of supported languages.

Quickly see which OneNote app you have on Windows
Convert a recording into text with Word’s Transcribe
Three extra audio formats that work with Microsoft 365’s Transcribe