I have random accounts on my Xbox One that I don't use anymore. I don't want to completely delete them, I just want to take them off of my Xbox.
You can do so from the Account option in the settings as described here (second option under "Topics"). Keep in mind that if the accounts are secured by a password, you may need to provide it to be able to remove the account.
Removing accounts that are valid Xbox Live accounts will just remove them from the console, not delete them.