Configuring preferences and options in Outlook.com
Send email from a different email address
In the compose window, select Options > Show From to see the From line.
Select the down-arrow next to From and choose which email address you want to use.
- If you don't see all your accounts or aliases, select Other email address... and start typing the email address or name you want to send from.
If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.
hth
Marcin