If the account primary alias (email address) is from MS (hotmail, msn, outlook,...), and you either:
- delete the account
- change the primary alias (it doesn't matter to what)
your current MS email address will disappear and the currently accesible sent/received emails stored outside your computer will disappear. If the primary alias isn't from MS, neither of it will happen but you won't be able to use the same address for other or the same MS account.
I've never had an email address from an MS domain. This is just coincidental.
I have never used local accounts for Windows 10 or 11. I'm fine with the services an MS account provides.
For Edge (in 2 computers with 10 and 11 respectively) I'm using an MS account different from the one I'm using for the devices themselves. I did this setup w/o knowing well the advantages and disadvantages respect to just using the device account or no account (for Edge).
Maneuvering with the Edge profiles you can delete the favourites from the account, or you can delete the favourites so they're synchronized and hence deleted from the account.
Up to a certain Edge version from years ago, it was possible to use an MS account in Edge with sychronizing disabled maneuvering in the Edge GUI, since then you should use a registry key (or maybe there's a policy). There's an Edge GUI option to delete the synchronized stuff, but w/o the registry key (or policy if it exists) it will start to synchronize inmediately. If you only have one device in the account, the synchronizing is only between your computer and the MS servers.
If you just do a clean install with the same account, the favourites you have now will appear "magically" in the new install. The same if you use the same account for other device.
If you're using OneDrive, research your options seriously, b/c you may lose files you don't want to delete. I have never used OneDrive (I turned it off as orderly and soon as I could, but better research first if you don't know enough).
I'm using a PIN in my 2 relevant computers so I might have forgotten the account password. If you simply don't recall it, go to account.microsoft.com , enter your email address and use the "I've forgotten my password" or "Reset password" link. MS will send you an email (*) with digits to introduce in the web (to be sure it's you and not an imposter), and once entered you'll get access to set a new password.
(*) Important: if you have never changed the account primary alias and you have never bothered to set a different "main security address" (not verbatim), the authentication digits will be sent to the "account main address" (verbatim this is called the "primary alias"), but in other cases they will be sent to the different "main security address" (typical case: I've updated the primary alias but not the "main security address", that sometimes is a dead address). In that case you have three options:
1. Change the "main security address" from a computer that has the old address set as
--- Edge profile address (confirmed, I was able to do it from a Windows 7 computer whose Edge had the address)
--- device account address (I suppose, but I haven't confirmed it)
2. Recover the account, what is a complicated process.
3. The MS account will expire if not used in 2 years I believe, except in certain corner cases (for example, the account has a balance, it was the case in the account I got to change its "main security address" from a Windows 7 b/c I had used it for a live.com profile associated to a game around 2011, and I've collected some redeemable "Xbox points").