On selecting all the required mailboxes, click on Apply for the changes to reflect.

You can then either enter the name of specific mailboxes separated by commas or import a CSV file containing the mailbox(es) details.Select the corresponding Microsoft 365 Tenant from the drop-down.Tick the Replace Existing Email Addresses option.Choose the Recipient Type and enter the email IDs to be modified.(can modify email IDs for both mailbox users and mail enabled users). Choose the Modify SMTP Address option.On selecting all the mailboxes, click on Apply for the changes to reflect.

Browse and import the CSV files containing the details of the mailbox user and modified user names.Select the corresponding Microsoft 365 Tenant.Choose the Mailbox Naming Attribute Changes option.Navigate to Exchange Online > Mailbox Management > Exchange Mailbox Tasks.This tool helps you to simultaneously modify the user names and mail IDs for multiple users. It's easy,simple to use and it redefines the Microsoft 365 management techniques. M365 Manager Plus is an intuitive Microsoft 365 reporting, managing, monitoring, auditing, and alerting tool. To perform bulk changes, you need an effective Microsoft 365 management solution like M365 Manager Plus. But what if you want to do it for multiple users all at once? There's no way Microsoft 365 admin center can help you with this. There, you can choose a particular user and change their email ID and display name. If you wish to change a user’s display name or email address, you can do so using Microsoft 365 admin center by navigating to Users > Active users > Account tab.

Change name in microsoft account