Managing personal Outlook.com account settings, security, and privacy
Dear Philip01,
Welcome to Microsoft Community.
I understand that you want to show only your christian name in your email and not your last name.
I'm sorry to say that Microsoft accounts really don't have this feature that gives you the option to show other people only your first name and not your full name.
However, other people can fill in only the first name and not the last name when they save you as a contact, so that when he receives your email, it will only show your first name and not your full name.
You can also contact online support for feedback, click on this page Contact - Microsoft Support
Please follow the steps below to contact the Microsoft Online Support:
1. Enter “account issue” to search and Click "Sign in to contact Support" at the bottom of the page.
2. Log in to your Microsoft account. Please be sure to log in with your personal account.
- Under Products & Services, select "Other Products".
- Under Categories, select "Manage account security", and click Confirm.
- Click "Chat with a support agent in your web browser".
Please contact online support during business hours in your area.
Feel free to post back if you need further assistance.
Best Regards,
Jason.YA - MSFT | Microsoft Community Support Specialist