We are currently using Office365 (Business Plan) for our MS Office products (No Exchange), and use the login lastname@ourcompany.onmicrosoft.com. Hopefully, we will be migrating to an E3 plan with Exchange next year.
As you can guess, users do not know that their login is lastname@ourcompany.onmicrosoft.com rather than lastname@ourcompany.com
Is it possible to add our domain to O365 to change usernames? Will it complicate migrating Exchange in the future?
I should point out that we have no AD, and hopefully if users could set their password for lastname@ourcompany.com it would help our migration.