Set Up User List
Office 365 has a few ways to configure your list of users. You can add them manually and generate a new account for each user as you go. For larger organizations this can be tedious and introduce the possibility of human error. Transferring from an existing list might be the best way to get started with your migration.
You can add a long list of users by creating and uploading a spreadsheet containing multiple users. You will create the spreadsheet and save it in a comma-separated value (CSV) file. Your spreadsheet file should look something like this:
Your spreadsheet file should look something like this:
Enterprises with existing Microsoft infrastructure, such as Active Directory or Exchange, can use migration tools to automatically replicate the Active Directory user list or each Exchange mailbox. But you are usually advised to limit yourself to smaller user groups, essentially performing multiple small migrations over time.
Beyond those options, there are a few other more complex methods to get your user list into Office 365. A managed services company that’s experienced in migration can assist with these kinds of configurations.
Once you have your list imported, you can create user accounts. Users will receive notification about their new account on your old email system. At this point, Office 365 isn’t quite ready for business, so everyone should be aware that the existing system is still fully functional and they should wait for your official notification that everything is “turned on.”