Create a Shared Mailbox in Office 365

A shared mailbox allows a group of people to monitor and send email from a common email addresses, like info@protectedtrust.com.

Note: You will need to have admin privileges to perform this task
  1. Open up a web browser to admin.microsoft.com and login with your credentials

  2. On the left side select the exchange admin center

  3. On the welcome screen you can select shared, under recipients, or you can click Recipients on the left side then click shared.

  4. Click the '+' sign to create a new mailbox.

  5. A box will appear. Here you will create your display and email addresses.

  6. You can also choose who you would like to have access to the mailbox. Just click the plus side and select one or multiple users, click add and click OK.

  7. If you click more options, you can add an alias for the shared mailbox as well.

  8. After you have chosen your options click save.

Your new shared mailbox should be now displayed in the list.

Note: We recommend that you block sign in for the shared mailbox that you create to keep the account secure.

 

 Source: https://docs.microsoft.com/en-us/office365/admin/email/create-a-shared-mailbox?view=o365-worldwide