Updated: 08 October 2023
Work or School/University accounts.
Can be aliased to an email address or telephone number.
My Account portal for work or school accounts https://myaccount.microsoft.com/
Customer service telephone number, for business users, United Kingdom +44 (0)344 800 2400
onmicrosoft
When a company or school signs up for an Office 365 for Business subscription, Microsoft will create a new domain with this onmicrosoft.com domain for the company. For example, @contoso.onmicrosoft.com. The Office 365 admins of a company can create new user accounts with this @contoso.onmicrosoft.com domain and manage the data under this tenant.
Personal accounts.
Can be aliased to an email address or telephone number.
Login to a personal account http://outlook.live.com