You can use Import Addresses / Forwarders to create multiple email address or email forwarders. . Excel spreadsheet  (.xls) or comma-separated values ( .cvs ) can be used to create mutiple email addresses/forwarders.

1) Click on the “Import Addresses / Forwarders””  in the Mail area.

By clicking this you will get a section like below.

Click any one option, whether you would like to import email accounts or forwarders.

To Import data Excel spreadsheet files (.xls) or comma-separated values sheet (.csv), browse the file path in the text box under step 2

Click on “Next” for importing the file.