How to create a new Azure tenant for another company

Hi Marcin,

Thank you so much for your detailed clarification and solution.

Regarding the options you mentioned, the option "Create the second tenant (company2.onmicrosoft.com) but only use its default domain or add a different custom domain (e.g., apps.company.com, company2.com)" is what I mean.

As I mentioned initially, I need to create a new Azure tenant (whichever the xxx.onmicrosoft.com domain is, not need to algin with the domain company.com), but the root administrator is ******@company.com - that's fine.

=> So, from your comment, I understand that the only way to do this is:

1. Create a second tenant (company2.onmicrosoft.com) but only use its default or a different domain
2. Invite the ******@company.com to the 2nd tenant as a member and assign the "Global admin" role

Is it correct?

=> and how to create a new one using a default domain? Or do I need to use a personal email address to create the new first and then invite user@?

May I use the email address ******@company.com to create a new default domain tenant (xxx.onmcirosoft.com)?

Many thanks

Xolex

You can create a brand-new Entra ID (Azure AD) tenant at any time. Microsoft will automatically assign it a unique default domain like something.onmicrosoft.com. The account you use to create the tenant (sign-up email) becomes the first Global Administrator of that new tenant.

The custom domain company.com is already verified and tied to the existing tenant (company.onmicrosoft.com). You cannot add or verify company.com in the new tenant unless you first remove it from the existing tenant — which would break M365 for the customer. So the new tenant will only use its default domain (e.g., company2.onmicrosoft.com) or another custom domain you control (like apps.company.com).

You can absolutely sign up for a new tenant using ******@company.com. That email address does not have to belong to the new tenant. It just receives the invitation/verification email. In fact, that’s a common way to bootstrap a new tenant. Microsoft will create the new tenant and make ******@company.com the first Global Admin. The new tenant will not own company.com — it will just treat ******@company.com as an external admin identity.

To implement it, use the following procedure:

1. Go to the Azure Portal → top-right tenant switcher → Create a tenant.
   • Type: Entra ID (Microsoft Entra ID).
   • Give it a name (e.g., "Company Dev Tenant").
   • Microsoft assigns the default domain: company2.onmicrosoft.com.
2. After creation:
   • ******@company.com is the initial Global Admin in that tenant.
   • No need to use a personal email; your work email is fine.
   • Later, you can invite other users (e.g., more @company.com accounts) as guests and promote them to admins if needed.

In other words, your understanding is correct:

• Step 1: Create second tenant (company2.onmicrosoft.com, default domain).
• Step 2: Sign up with ******@company.com — that becomes Global Admin right away.
• Step 3 (optional): Invite additional @company.com users as members/guests and assign roles.

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