To add users in Business Central, your company's Office 365 administrator must first create the users in the Office 365 Admin Center.
Once users are created in Office 365, they can be imported into the Users window by using the Get Users from Office 365 action. Users are assigned permission sets depending on the plan assigned to the User in Office 365.
Important: If the database has multiple companies, then at least one user must be a member of the SUPER user group in all companies.
To add users to the Admin center
From the app launcher, select the admin icon
Once here, select add a user (or open the Active users list to view current users)
Create the user and assign the license information.
Next, click the waffle and go into Dynamics 365
Search for Users and open the page
Click Get users from Office 365 to pull in the users you just created.
Then assign permissions to the user.
The company you are in when you do this will default into the user’s permissions.
If you have more than one company and the user can access all companies, remove the company name from the user group and tab off the field. The system will ask you if you want to change the record, click yes/ok.
If you have multiple companies and the user can access some, but not all, you will need to add user groups/permission sets for each company they can access.
If you have configured a user to access some but not all companies, you will then want to go to the user personalization page to make sure the default company is one you have permission set for on the user card.