Microsoft announced via a Windows blog post that starting with Edge 83, a new spellcheck experience powered by Windows Spellcheck is coming to all Windows users on Windows 8.1 and up.
How to user spellcheck in Edge
For most users spellcheck just works, not setup required, but just in case, the related settings are located at edge://settings/languages.
If English is not your preferred language, you can add additional languages to spellcheck in Windows Settings by navigating to Time & Language -> Language and selecting Add a preferred language.
Edge 83 is now available in the stable channel, if you prefer a more private a secure chromium-based browser than try Brave.
Microsoft says that they collaborated with Google engineers in the Chromium project, which means that all Chromium based browsers like Brave, Vivaldi and others will benefit from the new Windows spellcheck integration.