Question: How to add SharePoint Users in Bulk through HC?

You can add bulk SharePoint Users in HC panel at Reseller/Tenant Admin level path: Hosting Services :: Manage SharePoint :: SharePoint Sites :: SharePoint Users :: Add Bulk Users

Below is the CSV format Bulk-SharePoint-Users.zip  
FirstName, LastName, EmailID, Password (This line must be on top in the csv file )

1. John, Peter, john@domain.com, W3lcome 
2. , , john@domain.com,W3lcome
   
   Note: Don't insert space after comma ',' 

P.S: 

• FirstName and LastName are optional and can be set empty. In such a case, firstname will be parsed from Email ID as first portion of email.
• EmailID and Password fields are necessary.