The Mappings window lets you create and edit how you want the information in your worksheet to match up with available fields in QuickBooks.
When you create a mapping, you create 1-to-1 pairings between QuickBooks fields and columns in your worksheet.
Import data column
Contains the columns from your Excel or CSV worksheet that can be
mapped to QuickBooks fields.
The drop-down list displays either column letters (A, B, C) or column headings (First Name, Phone, and so on) depending on two things:
Whether or not your worksheet contains column headings
Whether or not you selected the This data file has header rows checkbox in the Import a file window