Software & Apps MS Office How to Set the Default Email Account in Windows Mail or Outlook By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated February 07, 2020 The Windows 10 free Mail app. MS Office Outlook Word Excel Powerpoint Tweet Share Email In older, no-longer-supported versions of Microsoft's free, native email programs, you could add several accounts and then specify a default account for when you composed a new message. With the Mail app on Windows 10, however, although you can still add several accounts, clicking the New mail button opens a fly-out menu specifying the account from which the message will be sent. Because of the multi-account fly-out menu, it no longer makes sense to specify a default account. This functionality has been deprecated from Mail. Changing Address Information If you've set up an account through Office 365 or Microsoft Exchange, the server governs all information about the account, including your name and email address. If you've selected an IMAP account, however, you enjoy greater control over specifying the display name of the message. Adjust your display name for IMAP accounts by going to Settings > Manage accounts. Select the relevant account and modify the information as needed.