Adding text name to Person field in SharePoint Lists

Hi All,

Is there an easy way to add a person's text name i.e. John Doe to a person field in lists with it accepting it as an Office365 user?

I can easily do this for a single row/person by pasting in the text name to the Person field in grid view and then selecting John Doe from the Office365 address book.

This works for single entries but I need a bulk solution (> 500 rows), is this possible?