How to remove my last name as my legal name do not have a surname.

Update your Legal name on https://learn.microsoft.com/users/me/settingsand set your last name to the underscore _ character

Hello, thank you for reaching out to Microsoft Q&A.

You can sign in with your Microsoft account at the link below and edit your profile details, including your name.

https://account.microsoft.com/profile

Once you’re signed in, go to Your Info and update your name so it matches your government ID.

To remove your surname from your name in a Microsoft account or related services, you typically need to update your legal business profile if you are a partner or adjust your personal account settings if it's a personal account. However, if you are a CSP partner, you cannot change the country/region associated with your legal address, and certain changes might require a support request.

For personal accounts, you can usually update your name directly in the account settings. If you encounter issues or if the system does not allow you to make the change, you may need to contact support for assistance. Make sure that the name you provide matches your legal name on government IDs exactly, without any spelling errors or abbreviations.

If you are not able to make the change yourself, creating a support request with details of the issue may be necessary. Attach any relevant files that show the error you are encountering.

For further assistance, please refer to the Microsoft support documentation or contact their support team directly for guidance specific to your situation.